A method for producing a sheet made of an aggregate of flat powders made of any one of metals (excluding tin and zinc), alloys, metal oxides, and inorganic compounds, in which the gaps between the flat surfaces of the flat powders are joined by aggregates of metal or metal oxide nanoparticles.

Abstract

To provide a method for manufacturing a sheet made of a collection of soft magnetic flat powder.SOLUTION: In a method, a raw material for a substance that joins flat surfaces of flat powder is liquefied into a low-viscosity, low-density liquid, the flat surfaces of the flat powder are overlapped through the liquid, the flat surfaces is transformed into a nano-sized substance that joins the flat surfaces, the nano-sized substance is changed to the substance that joins flat surfaces, and after this, the flat surfaces are joined together by the collection of the substance, an organometallic compound that precipitates metal or metal oxides through thermal decomposition is dispersed in methanol, the methanol dispersion is interposed between the flat surfaces of the flat powder, the methanol is vaporized, the collection of fine crystals of the organometallic compound is deposited in the gaps between the flat surfaces of the flat powder, compressive stress is applied to the collection of flat powder to thermally decompose the fine crystals of the organometallic compound, the collection of metal or metal oxide nanoparticles is deposited, and the flat surfaces of the flat powder are joined together via the collection of nanoparticles joined together by frictional heat.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention provides Excluding tin and zinc The gaps between the flat surfaces of flat powder made of metal, alloy, metal oxide, or inorganic compound are joined via a collection of nanoparticles of metal or metal oxide joined by frictional heat. Ta The present invention relates to a method for producing a sheet consisting of a collection of such flat powder. Powders with a large aspect ratio, which is the ratio of the average value of the major axis and minor axis to the thickness, are variously described as flat powder, flake powder, scale powder, thin plate powder, disk powder, or thin plate powder, but in this invention they are described as flat powder. On the other hand, flat powders made of soft metals or glass are generally described as flake powder, and will be described as flake powder. The present invention first involves dispersing an organometallic compound, which is capable of precipitating a metal or a metal oxide upon thermal decomposition, in low-viscosity, low-density methanol, and then Excluding tin and zinc A suspension is produced in a container, in which flat surfaces of flat powder made of a material selected from metals, alloys, metal oxides, and inorganic compounds are stacked together. Next, methanol is evaporated from the suspension in the container, causing clusters of fine crystals of the organometallic compound to precipitate in the gaps between the flat surfaces of the flat powder and on the surfaces of the clusters. A plate is then placed over the entire surface of the clusters of flat powder, and the entire surface of the plate is evenly compressed to crush the clusters of fine crystals of the organometallic compound into clusters of even finer crystals. Then, while applying a compressive load evenly to the entire plate, the container is heated, causing the organometallic compound to thermally decompose, simultaneously precipitating clusters of metal or metal oxide nanoparticles in the gaps between the flat surfaces of the flat powder and on the surfaces of the clusters of flat powder. Furthermore, the nanoparticles are bonded to the flat surfaces by frictional heat, and the nanoparticles are also bonded to each other by frictional heat. This produces a sheet in the container in which the flat surfaces of the flat powder are bonded together via the clusters of nanoparticles bonded by frictional heat. Furthermore, if the flat powder is a soft magnetic flat powder of a metal or alloy, and the nanoparticle material has a constant relative magnetic permeability and at least one of the magnetic permeability loss in the complex magnetic permeability and the dielectric loss in the complex dielectric constant has a constant value, a sheet in which the flat surfaces of the flat powder are bonded together via a collection of nanoparticles can be used as a sheet with high electromagnetic wave reception sensitivity, electromagnetic noise absorption, and a sheet with a high magnetic shielding effect. Furthermore, if the flat powder is a metal or alloy flake powder, a sheet in which the flat surfaces of the metal or alloy flake powder are bonded together via a collection of metal nanoparticles with high electrical conductivity and thermal conductivity can be used as an antistatic sheet, an electromagnetic wave shielding sheet, a thermally conductive sheet, a sheet made of a metal or alloy with a highly lubricious surface, wiring for electrical equipment, an electrode, etc. Furthermore, if the flat surfaces of the metal or alloy flake powder are bonded together using highly transparent nickel or aluminum nanoparticles, a sheet with the luster of the metal or alloy can be obtained without losing the color of the metal or alloy. Furthermore, if the flat powder is an insulating flat powder made of glass, alumina, or hematite, a sheet in which the flat surfaces of the flat powder are bonded together via a collection of insulating metal oxide nanoparticles can be used as an insulating sheet with high insulation properties. Furthermore, if the flat surfaces of an inorganic luster pigment, in which the surfaces of flat powder made of glass or aluminum are coated with a film made of metal or metal oxide, are bonded together using highly transparent nickel or aluminum nanoparticles, a sheet with the gloss of the inorganic luster pigment can be obtained without losing the color of the inorganic luster pigment. The inventors have also filed a patent application (Japanese Patent Application No. 2020-139002) for a method for producing a paste consisting of a collection of flat powders in which the flat surfaces of the flat powders overlap each other using a solution of an organic compound with a certain viscosity. In other words, the flat surfaces of the flat powders are overlapped using a solution of the organic compound, and then the solution of the organic compound is vaporized to create a collection of flat powders in which the flat surfaces of the flat powders overlap each other. Furthermore, one surface of the collection of flat powders is evenly compressed, and the flat surfaces of the flat powders are bonded together using frictional heat, producing a sheet consisting of the collection of flat powders. In contrast, the present invention produces a sheet in which the flat surfaces of flat powder are bonded together via a collection of metal or metal oxide nanoparticles bonded by frictional heat. To this end, an organometallic compound that precipitates metal or metal oxide upon thermal decomposition is dispersed in methanol, which has both low viscosity and density, and the flat surfaces of the flat powder are overlapped via the methanol dispersion. The collection of flat powder is then compressed, and the organometallic compound is further thermally decomposed, and the flat surfaces of the flat powder are bonded together via a collection of metal or metal oxide nanoparticles bonded by frictional heat. In other words, because the flat surfaces of the flat powder are not completely flat, even if the collection of overlapping flat powder is evenly compressed, the flat powders are not bonded together by frictional heat across the entire surface, but only in part of the flat surfaces. Therefore, the poorer the flatness of the flat powder, the weaker the bonding strength between the flat surfaces. In contrast, in the present invention, the entire surfaces of the flat powder are bonded together with a collection of nanoparticles that are two or more orders of magnitude smaller than the area of ​​the flat surfaces. Therefore, even if the flatness of the flat powder is low or the flat surfaces are uneven, the nanoparticles are nearly two orders of magnitude smaller than the unevenness of the flat surfaces, so regardless of the flatness of the flat surfaces and the surface unevenness, the entire surfaces of the flat surfaces are bonded together with the collection of nanoparticles, increasing the bonding strength between the flat powders. Furthermore, in the bonding of flat surfaces in the present invention, the size of the nanoparticles precipitated in the gaps between the flat surfaces is small, around 10 nm, and the deposition density of the nanoparticles is high. Therefore, when compressive stress is applied to the nanoparticle cluster, the nanoparticles are difficult to move, increasing the strength of the nanoparticles bonding to the flat surfaces and the bonding strength between the nanoparticles themselves. For this reason, in the present invention, the clusters of fine crystals of the organometallic compound precipitated in the gaps between the flat surfaces are crushed to their limiting size, and the finer crystal clusters are stacked at high density in the gaps between the flat surfaces. After this, a compressive load is applied to the entire cluster of flat powder with overlapping flat surfaces, and the finer crystals of the organometallic compound are thermally decomposed. Nanoparticles of metal or metal oxides, around 10 nm in size, are deposited simultaneously in the gaps between the flat surfaces, stacked at high density. Furthermore, when stress is applied to the cluster of nanoparticles, the nanoparticles are bonded to the flat surfaces by frictional heat, and the nanoparticles are also bonded to each other by frictional heat. This allows for the production of sheets with various properties that are made up of an aggregate of flat powder particles with increased bonding strength between the flat powder particles. [Background technology]

[0002] There are four types of powders with flake or flat surfaces made of either metal, alloy, metal oxide or inorganic compound: soft magnetic flat powder made of metal or alloy, flake powder made of metal or alloy, insulating flat powder made of metal oxide or inorganic compound, and inorganic lustrous pigments in which the surface of flat powder made of glass or aluminum is coated with a film made of metal or metal oxide. First, we will explain the background art related to soft magnetic flat powder made of metal or alloy. If the flat surfaces of soft magnetic flat powder can be joined together, a sheet made of an aggregate of flat powder can be formed. Taking advantage of the complex permeability of the flat powder, this sheet can absorb electromagnetic noise. Also, taking advantage of the relative permeability of the flat powder, this sheet can be used as a magnetic shield. Meanwhile, electronic devices that use high-frequency signals, such as mobile phones and personal computers, have become increasingly popular in recent years. For example, some mobile phones and wireless LANs use high-frequency signals ranging from several GHz to 10 GHz. Furthermore, as the signals used by electronic devices become higher in frequency, and as electronic devices become smaller, thinner, and more powerful, malfunctions caused by electromagnetic interference within the electronic devices and interference caused by noise radiated to the outside of the devices have become problems. For this reason, the International Special Committee on Radio Interference (CISPR) issued the standard CISPR22 in 2005, which regulates electromagnetic noise up to 6 GHz.

[0003] The electromagnetic noise absorption energy P is given by Equation 1. The first term is the absorption of electromagnetic noise based on the properties of soft magnetism, where magnetic loss occurs depending on the magnitude of the imaginary part μ" of the complex permeability and the frequency, and this magnetic loss is converted into heat. The second term is the absorption of electromagnetic noise based on the properties of a dielectric, where dielectric loss occurs depending on the magnitude of the imaginary part ε" of the complex permittivity and the frequency, and this dielectric loss also converts into heat. The third term is the absorption of electromagnetic noise based on conductivity, where conductive current flows on the surface due to the skin effect of the high-frequency electric field, forming a resistive film, and this resistive film generates resistive loss depending on the magnitude of the conductivity σ, and this resistive loss also converts into heat. Therefore, if an electromagnetic noise absorbing sheet has a certain magnitude of the imaginary part μ" of the complex permeability or a certain magnitude of the imaginary part ε" of the complex permittivity within the frequency band of electromagnetic noise, it will absorb electromagnetic noise within a certain frequency band. In Equation 1, E is the magnitude of the electric field in the electromagnetic noise, H is the magnitude of the magnetic field in the electromagnetic noise, f is the frequency of the electromagnetic noise, and σ is the conductivity. When a magnetic material receives an alternating magnetic field in the electromagnetic noise, a phase delay occurs in the change in magnetic flux density, and the permeability is given by μ'-jμ", which is the difference between the real part μ' and the imaginary part μ". Alternatively, when a dielectric material receives an alternating electric field in the electromagnetic noise, a phase delay occurs in the change in electric flux density, and the permittivity is given by the difference ε'-jε". (Number 1) P=πfμ”H 2 +πfε”E 2 +1 / 2 σE 2

[0004] Traditionally, the performance of electromagnetic noise absorption sheets has been determined based on the magnetic permeability of the soft magnetic material that makes up the sheet. For electromagnetic noise up to around 100 MHz, the magnetic flux converging effect of the soft magnetic material's complex permeability (μ') shields the magnetic field, providing a magnetic shielding effect. Furthermore, the magnetic loss effect of the imaginary part of the complex permeability (μ") absorbs electromagnetic noise and converts it into heat, thereby suppressing it. However, for many soft magnetic materials, the real part of the complex permeability decreases at frequencies just before 100 MHz, and the larger the real part, the more rapidly it decreases. This phenomenon is known as the snake's limit, where the larger the real part of the complex permeability of ferrite, the more rapidly the real part decreases above 10 MHz. Meanwhile, the imaginary part of the complex permeability increases sharply just before the frequency at which the real part peaks, peaks at a certain frequency, and decreases the further away from the peak frequency it is, failing to achieve the required magnitude above 500 MHz.

[0005] On the other hand, if the imaginary part of the complex permittivity of a dielectric has a certain magnitude in the frequency band above 500 MHz, the dielectric loss of the dielectric material based on Equation 1 will absorb electromagnetic noise in the frequency band above 500 MHz. In other words, the dielectric dipoles (called orientation polarization) cannot keep up with changes in the electric field above 500 MHz, causing dielectric dispersion, which reduces the dielectric constant of the dielectric. This phenomenon occurs when a phase lag occurs in the change in electric flux density in the alternating electric field of electromagnetic noise, as explained in paragraph 3. However, in the frequency band above 500 MHz, the imaginary part of the complex permittivity of most solid dielectrics is small. This is explained below using the imaginary part of the complex permittivity of a dielectric at 2.45 GHz, the frequency used in microwave ovens. The imaginary part of the complex permittivity of polymeric materials at 2.45 GHz is 0.2-0.5 for phenolic resin, 0.16-0.23 for urea resin, 0.08-0.25 for vinyl chloride resin, 0.12-0.28 for polyamide resin, 0.03-0.42 for cellulose resin, 0.027-0.03 for synthetic rubber, and 1.2 × 10 for polyethylene resin. -3 And polypropylene resin is 4 x 10 -4The imaginary part of the complex permittivity of all polymer materials is small. On the other hand, the imaginary part of the complex permittivity of water, a typical polar molecule, is large at 22.0. For this reason, the magnitude of the imaginary part of the complex permittivity of water at 2.45 GHz is used as the principle of heating food in microwave ovens. In other words, when food is irradiated with microwaves of 2.45 GHz, the water molecules contained in the food cannot keep up with the change in the electric field, and absorb the microwaves due to dielectric loss, converting them into heat. On the other hand, the imaginary part of the complex permittivity of ice at 2.45 GHz is 2.8 x 10 -4 is small. For this reason, ice does not melt when exposed to microwaves. In this way, with the exception of liquids made up of polar molecules such as water, alcohol, and acetone, the imaginary part of the complex permittivity of many substances in the frequency band above 500 MHz is small, and they are unable to absorb electromagnetic noise in the frequency band above 500 MHz.

[0006] Electromagnetic waves have a skin depth. Skin depth is the distance at which the electromagnetic field of an electromagnetic wave incident on a sheet made of a soft magnetic material decays to 1 / e (equivalent to 0.368). Skin depth is inversely proportional to the square root of the product of the frequency of the electromagnetic wave, the complex permeability of the flake powder, and the conductivity of the flake powder. Therefore, the higher the frequency of the electromagnetic wave, the greater the complex permeability of the flake powder, and the greater the conductivity of the flake powder, the shallower the skin depth. Therefore, by utilizing the skin effect, sheets made of soft magnetic materials can be made thinner and lighter. Therefore, by adjusting the thickness of a sheet made of soft magnetic material according to the frequency band of the electromagnetic waves to be absorbed and constructing the sheet to the required thickness, less soft magnetic material is used, resulting in a lighter sheet. Similarly, for magnetic shielding sheets, adjusting the thickness of a sheet made of soft magnetic material according to the frequency band of the electromagnetic waves to be shielded and constructing the sheet to the required thickness results in a lighter sheet using less soft magnetic material.

[0007] Patent Document 1 discloses a sheet made of a new material configuration as a sheet that absorbs electromagnetic waves. That is, the sheet absorbs electromagnetic waves using magnetic fine particles, and includes a first magnetic layer made of a polymeric material in which the magnetic fine particles are dispersed, a non-magnetic layer made of a polymeric material formed on the first magnetic layer, and a second magnetic layer made of a polymeric material in which the magnetic fine particles are dispersed, formed on the non-magnetic layer, in which the direction of the easy axis of magnetization in the first magnetic layer is different from the direction of the easy axis of magnetization in the second magnetic layer. In other words, this is an electromagnetic wave absorbing sheet that aims to efficiently absorb electromagnetic waves by using a second magnetic layer that has a different easy axis direction from that of the first magnetic layer, even if electromagnetic waves are radiated in a direction that cannot be efficiently absorbed by the first magnetic layer. However, if the magnetic material that absorbs electromagnetic waves is not a fine particle but a flat powder with a certain area, a sheet can be formed by randomly joining the flat surfaces in the direction of the axis of easy magnetization, eliminating the need to form the three layers described in Patent Document 1, and making it possible to form an inexpensive sheet.

[0008] Patent Document 2 discloses a flat powder of an alloy with even higher magnetic permeability, which is obtained by intentionally deviating from the composition of an Fe-9.6%Si-5.4%Al alloy, which is an alloy powder with high magnetic permeability. Patent Document 2 describes an example of a sheet using flat powder of this alloy, in which chlorinated polyethylene is dissolved in toluene, flat powder of the alloy powder is mixed into this solution, and then the mixture is applied to polyester resin and dried, and then pressed at 130°C and a pressure of 15 MPa to produce a composite sheet, which is a sheet with high magnetic permeability. However, chlorinated polyethylene resin is non-magnetic and does not contribute to electromagnetic wave absorption or magnetic shielding. Therefore, the electromagnetic wave absorption and magnetic shielding performance of a composite sheet decreases depending on the volume ratio of non-magnetic chlorinated polyethylene resin. It has also been reported that alloy flake powder has high magnetic permeability when its flatness ratio is 15 or higher. However, to reflect the magnetic permeability characteristics of flake powder with a high flatness ratio in a composite sheet, the flat surfaces must be aligned in the same direction as the sheet surface, so that the collection of flat powder efficiently contributes to electromagnetic wave absorption and magnetic shielding. However, simply mixing flat powder with a size of tens of microns or less into a chlorinated polyethylene solution and applying this mixture does not align the flat surfaces of the flat powder in the same direction as the sheet surface. Thus, even if the magnetic permeability characteristics of a soft magnetic material are excellent, unless the magnetic permeability characteristics of the soft magnetic material are reflected in the structure of the sheet, the sheet will not reflect the magnetic permeability characteristics.

[0009] Next, we will explain the background art related to flake powder made of metal or alloy. If flat surfaces of flake powder made of metal or alloy can be bonded together to form a sheet consisting of an aggregate of the flake powder, the sheet can be used for antistatic sheets, electromagnetic wave shielding sheets, wiring for electrical devices, electrodes, and more. To form such conductive sheets, a conductive film is formed using a conductive paste. Conventional conductive pastes are composed of a fluid composition in which conductive fillers made of metal or alloy are dispersed in a vehicle consisting of a resin-based binder and a solvent. When the conductive paste is printed by a method such as screen printing, the conductive fillers are transferred to the printed substrate via a liquid substance. The liquid substance, consisting of a resin-based binder and a solvent, serves to transport the conductive fillers, and therefore the liquid substance is referred to as the vehicle. These conductive pastes are divided into two types: a resin-curing type in which conductive fillers are bonded together through the curing of the resin, forming an electrical path through the conductive fillers; and a fired type in which the organic components are volatilized by firing, sintering the conductive fillers together, and the sintered conductive fillers form an electrical path. Resin-curing conductive paste is a paste-like composition consisting of a conductive filler made of metal or alloy powder and an organic binder in which a thermosetting resin such as epoxy resin is dissolved. When heat is applied, the thermosetting resin cures and shrinks along with the conductive filler, and the conductive fillers are pressed together through the cured resin, bringing them into contact with each other and providing conductivity. This resin-curing conductive paste is heated at a low temperature of around 200°C, so it is less susceptible to heat damage and is used to form wiring on printed wiring boards and circuit boards made of heat-sensitive synthetic resins. On the other hand, sinterable conductive pastes are paste-like compositions in which conductive fillers made of metal or alloy powders and glass frit are dispersed in an organic vehicle. They are fired at high temperatures of around 900°C to volatilize the organic vehicle, melt the glass frit, and sinter the metal or alloy powders together, thereby achieving conductivity. The glass frit bonds the conductive film made of metal or alloy powder to the substrate, while the organic vehicle transforms the metal or alloy powder and glass frit into a liquid medium that allows printing. Because of the high firing temperature, sinterable conductive pastes cannot be used on printed wiring boards or circuit boards made of synthetic resins. However, the sintering and integration of the metal or alloy powders allows for low resistance, making them suitable for use in, for example, the internal electrodes of multilayer ceramic capacitors.

[0010] The conductive paste uses a metal powder or alloy powder as a conductive filler and is composed of a dispersion liquid in which the metal powder or alloy powder, or the metal powder or alloy powder and glass frit, are dispersed in a vehicle consisting of a resin binder and an organic solvent. The conductive film formed from this conductive paste has various problems resulting from the use of the metal powder or alloy powder as the conductive filler and the dispersion of this metal powder or alloy powder. The first problem is that the resistance of the conductive film formed by heat treatment of the conductive paste is higher than the resistance of the metal powder or alloy powder. In other words, in resin-curing conductive pastes, the insulating thermosetting resin prevents direct contact between metal powder particles or alloy powder particles. In fired conductive pastes, the low-conductivity glass frit prevents sintering between metal powder particles or alloy powder particles. This increases the electrical resistance of the wiring, electrodes, electromagnetic wave shielding film, antistatic film, and other components of the electrical circuit formed by heat treatment of the conductive paste, resulting in electrical energy loss and heat generation, which can cause defects. The second problem is the dispersibility of the metal or alloy powder. In other words, if the dispersibility of the metal or alloy powder aggregates in the vehicle is poor, the metal or alloy powder will be unevenly distributed after heat treatment, preventing direct contact between the metal or alloy powder particles. As a result, as mentioned above, the electrical resistance of the wiring, electrodes, electromagnetic wave shielding film, and antistatic film of the electrical circuit formed by heat treatment of the conductive paste will increase. The third issue is that when metal powders or alloy powders are sintered together, the metal powders or alloy powders shrink, which can cause structural defects in the internal electrodes of multilayer ceramic capacitors, such as delamination between the electrode and dielectric and cracks in the electrode layers. The fourth problem is that metal powders or alloy powders tend to aggregate together. Furthermore, the finer the powder, the more likely it is to aggregate. When powder aggregation occurs, the powder becomes less dispersible in the vehicle, which results in an increase in the electrical resistance of the conductive film formed by heat treatment of the conductive paste. All four of the above problems are caused by the use of metal powder or alloy powder as the conductive filler and the dispersion medium that disperses the aggregates of this metal powder or alloy powder, and therefore fundamental solutions are difficult to find.

[0011] Various attempts have been made to solve the problems associated with conductive films using conductive pastes. For example, Patent Document 3 describes a conductive paste that does not contain a resin component as a binder, and is composed of a metal powder filler in which a metal powder of a relatively base metal is coated with a relatively noble metal, metal nanoparticles coated with a coating agent, and an organic solvent. To disperse the metal nanoparticles in the conductive paste, the metal nanoparticles are coated with an alkylamine that has affinity for the organic solvent and a boiling point close to that of the organic solvent. When the applied conductive paste is heat-treated, the metal nanoparticles precipitate, and the metal filler is bound by the metal nanoparticles, forming a conductive film that does not contain a resin component. However, metal nanoparticles are extremely prone to aggregation, and once aggregated, they become nano-sized particles, making them difficult to disaggregate and difficult to handle. Furthermore, when generating metal nanoparticles, the generated metal nanoparticles easily aggregate with each other. For this reason, it is not possible to adsorb alkylammines onto the generated metal nanoparticles. Instead, metal nanoparticles coated with alkylammines are produced by precipitating metal nanoparticles in a liquid containing alkylammines, covering the metal nanoparticles with alkylamines, and evaporating the liquid components except for the alkylammines. For this reason, the manufacturing cost of coating metal nanoparticles with alkylamines far exceeds the manufacturing cost of conductive pastes. Consequently, versatile conductive films such as those for electrical circuit wiring, electrodes, electromagnetic wave shielding films, and antistatic films become expensive. Patent Document 3 describes the use of alkylammine-coated metal nanoparticles as a conductive paste, but does not describe a manufacturing method for coating metal nanoparticles with alkylamines.

[0012] Patent Document 4 describes a conductive paste made of silver oxide and a fatty acid silver salt having one or more amino groups. That is, when a coating film coated with the conductive paste is heat-treated, the fatty acid silver salt is decomposed into silver by the heat treatment, and the fatty acid or its decomposition products produced by the decomposition are volatilized, while some of the fatty acid produced by the decomposition reacts with silver oxide to produce a fatty acid silver salt again, and this fatty acid silver salt is decomposed into silver and fatty acid, repeating this cycle to form a conductive film made of silver. However, fatty acid silver salts containing one or more amino groups are produced by dissolving at least one hydroxyl-containing α-amino acid, selected from 2-aminoisobutyric acid, DL-threonine, DL-serine, DL-norvaline, and 6-aminohexane, in a solvent such as butyl carbitol, methyl ethyl ketone, isophorone, or α-terpineol, adding silver oxide powder to the resulting solution, and allowing the mixture to react at room temperature for a long period of time. Therefore, the cost of producing fatty acid silver salts using these specialized chemicals far exceeds the cost of producing conductive pastes. Therefore, as with Patent Document 3, versatile conductive films, such as those used in electrical circuit wiring, electrodes, electromagnetic wave shielding films, and antistatic films, are expensive.

[0013] Next, we will explain the background art related to insulating flat powders made of glass, alumina, or hematite. When describing flat glass powder as a type of insulating flat powder, it is referred to as flat glass powder. When describing flat glass powder as an individual flat powder, it is referred to as glass flake powder. This is because flat glass powder is generally called glass flake powder. Since silica flat powder is thin, with a thickness of 0.1 μm or less, there is a risk of it breaking when the flat surfaces are bonded together with a collection of metal oxide nanoparticles, so it was excluded from the category of insulating flat powders. Furthermore, mica and boron nitride flat powders were excluded from the category of insulating flat powders because the interlayer bonds between the crystals are easily broken by shear stress, causing crystal pieces to peel off from the flat powder when the flat surfaces are bonded together. The electrical resistivity of flat powders made of glass and alumina is 10 14 It has a high insulating property of more than Ωcm. Therefore, if the flat surfaces of the flat powder can be joined together with a group of highly insulating metal oxide nanoparticles, an insulating sheet with extremely high insulating resistance will be formed. Of the glass flake powders, only soda lime glass has a high insulating property of 10 12 The flat powder of hematite (a substance consisting of the alpha phase of ferric oxide Fe2O3) has an electrical resistivity of 10 8However, if the thickness of the flat powder is submicron and the cross-sectional area of ​​the flat powder of hematite is 0.3 μm × 10 μm, the electrical resistance per unit length of the flat powder is 3.3 × 10 16 Ω / cm. On the other hand, the electrical resistance of a collection of flat powders where the flat surfaces overlap each other is such that the electrical resistance of an extremely large number of flat powders forms a series and parallel connection, and an insulating film made up of a collection of hematite flat powders exhibits high insulation properties. Hematite flat powder is a red pigment known as red iron oxide, and is a general-purpose flat powder. On the other hand, when excessive compressive stress is applied to the flat surfaces of many insulating flat powders, the flat powder does not undergo plastic deformation but undergoes brittle fracture. Therefore, when joining flat surfaces together, it is necessary to join them in a way that does not apply excessive stress to the flat surfaces. In addition, it is necessary that the material used to join the flat surfaces does not reduce the insulating properties of the flat powder. As explained above, flat powders made of glass, alumina, or hematite are excellent raw materials for forming insulating sheets. However, there have been no examples to date of joining flat surfaces of insulating flat powders together in a way that does not apply excessive stress to the flat surfaces and does not reduce the insulating properties of the flat powders. In addition, there are inorganic luster pigments with excellent luster, in which the surface of flat powder made of glass or aluminum is coated with metals such as gold, silver, or nickel, or metal oxides such as titanium oxide or iron oxide, by electroless plating. However, to date, inorganic luster pigments have only been used as pigments. In contrast, if the flat surfaces of flat powder of inorganic luster pigments could be bonded together with a transparent material, a sheet consisting of an aggregate of flat powder of inorganic luster pigments could be created without losing the color reflected from the luster pigment. Furthermore, if a sheet consisting of an aggregate of flat powder of multiple types of luster pigments is created using multiple types of luster pigments that reflect different colors, the color tone reflected by the sheet can be changed to various colors by combining multiple types of luster pigments. However, there has been no example to date of bonding the flat surfaces of flat powder of inorganic luster pigments with a transparent material in a way that does not damage the metal oxide coating such as titanium oxide or iron oxide. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-198873 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-118114 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-035974 [Patent Document 4] Japanese Patent Application Laid-Open No. 2010-102884 [Non-patent literature]

[0015] [Non-Patent Document 1] Sanyo Special Steel Technical Report, VOl.13, No.1, 53-61 Summary of the Invention [Problem to be solved by the invention]

[0016] First, a problem that occurs when forming a sheet made of an aggregate of flat powder particles in which the flat surfaces of soft magnetic flat powder particles are joined together will be described. It is known that when soft magnetic powder is flattened in the plane direction, which is the axis of easy magnetization, the demagnetizing factor decreases, and the greater the flattening ratio, the greater the imaginary part μ" of the complex permeability. Furthermore, with the exception of ferrite, soft magnetic powder is made of metal or alloy, and is therefore conductive. For this reason, the magnitude of the imaginary part μ" of the complex permeability and the magnitude of the conductivity of conductive soft magnetic flat powder in equation 1 described in paragraph 3 contribute to the absorption of electromagnetic noise. Furthermore, the flattening process for soft magnetic powder does not rely on long batch processing using a ball mill, but rather on attrition processing of atomized soft magnetic powder or reduced soft magnetic powder using a media agitation mill, which allows flattened powder to be obtained continuously in a short period of time, making it an inexpensive process to manufacture. On the other hand, a sheet made of a collection of flat powders in which the flat surfaces of soft magnetic flat powders are overlapped and the overlapping flat surfaces are bonded with a substance having a constant value for at least one of the imaginary part of the complex permeability or the imaginary part of the complex permittivity can be formed into a sheet with a large area using a small amount of flat powder. Furthermore, because the flat surfaces form the sheet surface, all of the flat surfaces participate in absorbing electromagnetic waves, resulting in a sheet with high electromagnetic wave reception sensitivity and excellent electromagnetic wave absorption performance. This sheet maximizes the flat effect of the soft magnetic flat powder. Furthermore, if the thickness of the sheet can be freely adjusted according to the frequency band of the electromagnetic waves to be absorbed, the skin effect can be utilized, resulting in a lightweight sheet using less flat powder. On the other hand, the magnitude of the imaginary part of the complex permeability of soft magnetic flat powder depends on the frequency band of the electromagnetic waves. Furthermore, the magnitude of the imaginary part of the complex permeability of the flat powder and the frequency characteristics of the imaginary part of the complex permeability vary depending on the material of the soft magnetic powder. Therefore, if multiple types of soft magnetic flat powder have a constant magnitude of the imaginary part of the complex permeability in different frequency bands, and the frequency characteristics of the imaginary part of the complex permeability of each flat powder complement each other in different frequency ranges, then by overlapping the flat surfaces of the multiple types of flat powder and joining the overlapping flat surfaces together, electromagnetic noise over a wide frequency band can be absorbed. Furthermore, a sheet made of flat powder, in which the flat surfaces of soft magnetic powder are overlapped and the overlapping flat surfaces are bonded together with a material having a certain magnetic permeability, can be used as a magnetic shielding sheet. In other words, the higher the magnetic permeability of the flat powder in a DC magnetic field and the lower the magnetic resistance, the easier it is for magnetic lines to flow through the sheet, resulting in a greater magnetic shielding effect. On the other hand, since magnetic resistance is inversely proportional to magnetic permeability, a sheet made by overlapping flat surfaces of soft magnetic powder with a high relative magnetic permeability and bonding the overlapping flat surfaces together can have a high magnetic shielding effect. Furthermore, a large-area sheet can be formed using a small amount of flat powder, and since the flat surfaces form the sheet surface, all of the flat powder participates in magnetic shielding, enhancing the magnetic shielding effect. Furthermore, by adjusting the sheet thickness depending on the frequency band of the electromagnetic waves to be shielded, the skin effect can be utilized, resulting in a lighter sheet using less flat powder. In this way, a collection of flat powders in which the flat surfaces of soft magnetic flat powders are joined together provides excellent functions and effects as a sheet that absorbs electromagnetic noise and as a shielding film that shields magnetism. However, there have been no cases to date in which the flat surfaces of soft magnetic flat powders are joined together using a material in which at least one of the imaginary part of the complex permeability or the imaginary part of the complex permittivity has a constant value, or in which they are joined using a material with a constant magnetic permeability. As described in Patent Document 2, conventional sheets are made of a composite material in which the organic solvent in the binder is evaporated and flat powder particles are bonded together through the bonding of a solid polymer material. However, because the polymer material has different properties from the soft magnetic flat powder, the properties of the polymer material are reflected in the sheet. In this way, when soft magnetic flat powder particles are bonded together through the bonding of dissimilar solid materials that occupy a certain volume, the properties of the dissimilar materials are reflected, and the inherent properties of the soft magnetic flat powder are sacrificed. Furthermore, the flat surfaces do not form the sheet surface. In contrast, if a sheet can be formed from a collection of flat powders in which the flat surfaces of soft magnetic flat powders are joined together, the amount of flat powder used to form the sheet can be reduced, and the characteristics of the soft magnetic flat powder and the flat surfaces can be reflected in the sheet. Furthermore, if the flat surfaces form the sheet surface, all of the flat powder can participate in absorbing electromagnetic waves, or all of the flat powder can participate in magnetic shielding, resulting in a sheet that best reflects the magnetic properties of the soft magnetic flat powder. This results in an ideal sheet that can maximize the performance of the soft magnetic flat powder.

[0017] Next, a problem that occurs when forming a sheet made of an aggregate of metal flake powder in which the flat surfaces of the flake powder are joined together will be described. The four problems in forming conductive films described in paragraph 10 can be fundamentally solved if conductive fillers are not used when forming sheets. Therefore, if the flat surfaces of metal flake powder can be bonded together with a substance that has metallic properties, the four problems can be fundamentally solved. Furthermore, when joining flat surfaces of a flat powder made of an insulating metal oxide, it is sufficient if the flat surfaces can be joined together using an insulating material in a manner that does not apply excessive stress to the flat surfaces and does not reduce the insulating properties of the flat powder. Furthermore, if the flat surfaces of the inorganic luster pigment flake powder can be joined together with a transparent substance without damaging the coating of metal oxides such as titanium oxide and iron oxide, a sheet consisting of a collection of inorganic luster pigment flake powder can be created without losing the color reflected from the luster pigment. Therefore, the challenge of forming a sheet by bonding together flat surfaces of soft magnetic flake powder is to overlap the flat surfaces of the powder and bond the overlapping flat surfaces with a material having a constant value for at least one of the imaginary part of the complex permeability or the imaginary part of the complex permittivity, or with a material having a constant relative permeability. The challenge of forming a sheet by bonding together flat surfaces of metal flake powder is to overlap the flat surfaces of the powder and bond the overlapping flat surfaces with a material having metallic properties. Furthermore, for insulating flake powder, it is sufficient if the flat surfaces can be bonded together with an insulating material in a way that does not apply excessive stress to the flat surfaces. Furthermore, for inorganic luster pigment flake powder, it is sufficient if the flat surfaces can be bonded together with a transparent material without damaging the metal oxide coating. On the other hand, even if the flat surfaces of the flat powder are poorly flat or uneven, if the material bonding the flat surfaces is composed of a collection of nano-sized materials, the flat surfaces will be bonded to each other over the entire surface of the overlapping flat surfaces via the collection of nano-sized materials, regardless of the state of the flat surfaces, thereby increasing the bonding strength between the flat powders. Furthermore, if the thickness of the collection of nano-sized materials bonding the flat surfaces of the flat powders is thinner than the thickness of the flat powder, the area of ​​the flat powder is more than two orders of magnitude larger than the size of the nano-sized materials, and the properties of the sheet composed of the collection of flat powder will be dominated by the properties of the flat powder. Furthermore, when the flat surfaces are bonded to each other via the collection of nano-sized materials, the contact area between the nano-sized materials and the flat surfaces is extremely small. Therefore, when the nano-sized materials come into contact with the flat surfaces, excessive loads are not applied to the flat surfaces. Furthermore, the coating on the flat surfaces is not damaged. As a result, even flat powders prone to brittle fracture are not damaged. In addition, processes such as stress relief annealing to eliminate distortion caused by stress are not required. Furthermore, the luster of inorganic photoluminescent pigments is not lost. Therefore, it is necessary to overlap the flat surfaces of flat powders via nano-sized raw materials. On the other hand, it is possible to separate flat powders with directly overlapping flat surfaces into individual flat powders in a liquid. Furthermore, it is easy to overlap flat powders via a liquid. This is because liquids have the energy to allow molecules to move freely, and the shape of the liquid can change freely. Therefore, it is possible to generate shock waves in a liquid and apply them to flat powders with directly overlapping flat surfaces via the liquid, separating them into individual flat powders in the liquid. Furthermore, by applying a moving load to the liquid, flat powders with high aspect ratios can move in the liquid with their flat surfaces facing up, and the flat surfaces of the separated flat powders can be overlapped via the liquid. Furthermore, if the liquid is low viscosity and low density, shock waves can be easily transmitted through the liquid, and the flat surfaces can easily move in the liquid, making it easy to overlap the flat surfaces of flat powder that has been separated into individual flat powder sheets with a low viscosity and low density liquid in between.For this reason, the nano-sized material that bonds the flat surfaces must first be liquefied as a low-viscosity, low-density liquid, secondly separated into individual flat powders in the low-viscosity, low-density liquid, thirdly overlap the flat powder surfaces in the low-viscosity, low-density liquid and interpose the liquefied nano-sized material in the gaps between the flat powder surfaces, fourthly generate nano-sized materials from the liquefied nano-sized material, fifthly interpose a cluster of nano-sized materials in the gaps between the flat powder surfaces, and sixthly, if the cluster of nano-sized materials can bond the flat surfaces together, a sheet made of a cluster of flat powders is produced. To achieve this, the following six processes are required. The goal is to find a way to easily implement the six processes. First, the raw material nano-sized substance that bonds the flat surfaces of the flat powder together is liquefied into a low-viscosity, low-density liquid. Second, the low-viscosity, low-density liquid is used to separate the flat powder into individual pieces, and each piece is then covered with the low-viscosity, low-density liquid. Third, the flat surfaces of the flat powder are overlapped via the low-viscosity, low-density liquid. Fourth, the low-viscosity, low-density liquid present in the gaps between the flat surfaces of the flat powder is converted into a nano-sized substance that bonds the flat surfaces together. Fifth, the nano-sized substance is converted into a substance that bonds the flat surfaces together. Sixth, the flat surfaces are bonded together with the nano-sized substance to produce a sheet made of a collection of flat powder. [Means for solving the problem]

[0018] In the present invention Excluding tin and zinc A method for producing a sheet made of an assembly of flat powders, in which flat surfaces of the flat powders made of any one of metal, alloy, metal oxide, and inorganic compound are bonded together via an assembly of metal or metal oxide nanoparticles, comprises the steps of: Organometallic compounds that precipitate metals or metal oxides upon thermal decomposition In molecular state Dispersing the organometallic compound in methanol, and filling the methanol dispersion of the organometallic compound into a container. Excluding tin and zinc Metals, alloys, metal oxides or inorganic compounds 1 typeA mass of flat powder made of the material is weighed out so as to have a weight that is less than the weight obtained by multiplying the weight of the methanol by the ratio of the density of the flat powder used to the weight of the methanol, and the weighed mass of flat powder is put into the container, and the mass of flat powder is stirred in the methanol dispersion of the organometallic compound; further, a homogenizer device is placed in the container, and the homogenizer device is operated in the container, and shock waves are repeatedly applied to the mass of flat powder through the methanol dispersion of the organometallic compound; The collection of flat powders The mixture is separated into individual flat powders through the methanol dispersion of the organometallic compound, and the separated flat powders are covered with the methanol dispersion of the organometallic compound. After this, the homogenizer device is removed from the container. Furthermore, the container is covered in three directions, i.e., front and back, left and right, and up and down. impact Acceleration is repeatedly applied, and finally, impact Acceleration is applied to cause the methanol dispersion of the organometallic compound to penetrate into the gaps between the flat surfaces of the flat powder, and the methanol dispersion of the organometallic compound causes the flat powder to overlap with each other, forming a collection of the flat powder in the shape of the bottom surface of the container. Thereafter, the temperature of the container is raised to the boiling point of methanol, and methanol is evaporated from the methanol dispersion of the organometallic compound. consisting of a size smaller than 100 nm A cluster of microcrystals is precipitated in the gaps between the flat surfaces of the flat powder and on the surface of the cluster of flat powder. A plate material that covers the entire surface of the cluster of flat powder is placed over the entire surface of the cluster of flat powder, and the entire surface of the plate material is uniformly compressed to precipitate the microcrystals of the organometallic compound. It is about 20nm in size, which is about 1 / 5 of the size crushed into fine crystals, Furthermore, a compressive load is evenly applied to the entire surface of the plate material, and the temperature of the container is raised to the thermal decomposition temperature of the organometallic compound, thereby thermally decomposing the fine crystals of the organometallic compound. As a result, metal or metal oxide is deposited between the flat surfaces of the flat powder and on the surface of the aggregate of the flat powder. Consisting of a size of around 10 nmThe nanoparticle clusters overlap and precipitate simultaneously, and then the nanoparticle clusters are compressed, and the nanoparticle clusters are bonded to the flat surfaces of the flat powder by frictional heat, and the nanoparticles are also bonded to each other by frictional heat. As a result, a sheet made of the flat powder clusters, in which the flat surfaces of the flat powder clusters are bonded to each other, is formed in the container via the nanoparticle clusters bonded by frictional heat. The shape of the bottom of the container After that, the container is impact Applying acceleration, peeling the sheet made of the collection of flat powder from the bottom surface of the container, and removing the sheet from the container. Excluding tin and zinc Metals, alloys, metal oxides, or inorganic compounds 1 type A method for producing a sheet consisting of an aggregate of flat powder made of the above material, the flat surfaces of which are bonded together via an aggregate of metal or metal oxide nanoparticles.

[0019] The method for producing a sheet made of a collection of flat powder of the present invention involves the sequential implementation of the following eight simple processes, which produces a sheet made of a collection of flat powder in which the flat surfaces of the flat powder are bonded together via a collection of nanoparticles bonded by frictional heat. The first process involves dispersing an organometallic compound, which undergoes thermal decomposition to precipitate a metal or metal oxide, in methanol to prepare a methanol dispersion of the organometallic compound, and then filling the methanol dispersion of the organometallic compound into a container. Excluding tin and zinc A collection of flat powders made of any one of metal, alloy, metal oxide, and inorganic compound materials is weighed to a weight less than the weight obtained by multiplying the weight of methanol by the ratio of the density of the flat powder to the density of the methanol used, and the weighed collection of flat powders is placed in a container and stirred in a methanol dispersion of an organometallic compound. The third process is a process in which a homogenizer device is placed in the container and operated in the container. The fourth process is a process in which a homogenizer device is placed in the container in three directions and operated in the container. impact Acceleration is repeatedly applied, and finally, impactWhen these four processes are carried out consecutively, a collection of flat powder particles, with the flat surfaces of the powder particles overlapping each other, is formed on the bottom surface of the container in the shape of the bottom surface via the methanol dispersion of the organometallic compound. The fifth step is to heat the container to the boiling point of methanol. The sixth step is to cover the entire surface of the flat powder mass in the container with a plate that covers the entire surface of the flat powder mass, and evenly compress the entire surface of the plate to crush the fine crystals of the organometallic compound into even finer crystals. This causes the even finer crystals of the organometallic compound to accumulate at a high density in the gaps where the flat surfaces of the flat powder overlap and on the entire surface of the flat powder mass. The seventh treatment is to apply a compressive load evenly to the surface of the plate material, raise the temperature of the container to the thermal decomposition temperature of the organometallic compound, and thermally decompose the fine crystals of the organometallic compound. impact This is a process in which acceleration is applied and the sheet made of the collection of flat powder is peeled off from the bottom of the container, resulting in a sheet made of the collection of flat powder in which the flat surfaces of the flat powder are bonded together via collections of metal or metal oxide nanoparticles that are bonded by frictional heat. All eight processes are simple. Furthermore, organometallic compounds are common industrial chemicals. Therefore, it is possible to inexpensively produce sheets made of a collection of flat powder particles, with the flat surfaces of the particles bonded together via a collection of metal or metal oxide nanoparticles. The highest thermal decomposition temperature of organometallic compounds is 330°C in air. Among soft metals, tin has an extremely low melting point of 232°C, exhibiting low-temperature brittleness at temperatures around -40°C. Zinc also exhibits low-temperature brittleness. On the other hand, flat powders of metals, alloys, metal oxides, or inorganic compounds other than tin and zinc have melting points above 330°C and do not exhibit low-temperature brittleness, making them suitable for use at extremely low temperatures. Therefore, sheets made of flat powders with their flat surfaces bonded together can be used in harsh environments, such as high temperatures, extremely low temperatures, vacuums, and high pressures. Therefore, flat powders made of metals, alloys, metal oxides, or inorganic compounds other than tin and zinc can be used as raw materials for producing sheets made of flat powders. Here, the phenomena occurring in each process and the effects of each process will be explained. In the first treatment, when an organometallic compound that precipitates a metal or metal oxide by thermal decomposition is dispersed in methanol, the organometallic compound becomes molecular and disperses in the methanol. In contrast, when an organometallic compound dissolves in methanol, the metals that make up the organometallic compound become metal ions and dissolve in the methanol, making it impossible to return the dissolved organometallic compound to its original state. Therefore, when methanol is evaporated from a methanol solution of an organometallic compound, the original organometallic compound does not precipitate. Therefore, an organometallic compound that does not dissolve in methanol but disperses in methanol is used as the organometallic compound that precipitates a metal or metal oxide by thermal decomposition. In the second process, Excluding tin and zinc A collection of flat powders made of any of metals, alloys, metal oxides, and inorganic compounds is weighed to a weight that is less than the weight obtained by multiplying the weight of methanol by the ratio of the density of the flat powders used to the density of the methanol, and the weighed collection of flat powders is placed in a container. Excluding tin and zinc Among flat powders made of metals, alloys, metal oxides or inorganic compounds, permalloy has the highest density, and the density of permalloy with a nickel content of 45% is 8.25 g / cm 3 On the other hand, the density of methanol is 0.792 g / cm 3Therefore, the density of permalloy is 10 times higher than that of methanol. Also, organometallic compounds can be dispersed in methanol up to about 10% by weight, but the density of organometallic compounds is 1 g / cm 3 The density of a methanol dispersion of an organometallic compound is close to that of methanol. Furthermore, the viscosity of a methanol dispersion of an organometallic compound in which the organometallic compound is dispersed in methanol to a concentration of approximately 10% by weight is close to that of methanol. The viscosity of methanol, however, is extremely low at 0.59 mPa·sec. Therefore, when using flat permalloy powder, the weight of the cluster of flat permalloy powder is less than 1 / 10 of the weight of the methanol dispersion of the organometallic compound. On the other hand, the density of permalloy is 10 times the density of methanol. Therefore, the volume ratio of the methanol dispersion of the organometallic compound is greater than the volume ratio theoretically calculated from the weight of the cluster of flat permalloy powder. Therefore, when a cluster of flat permalloy powder is stirred in a methanol dispersion of an organometallic compound with a large volume ratio, the flat permalloy powder disperses well in the low-density, low-viscosity methanol dispersion of the organometallic compound, and is evenly mixed in the methanol dispersion. On the other hand, Excluding tin and zinc Among flat powders made of metals, alloys, metal oxides, or inorganic compounds, the flat powder with the lowest density is 2.7 g / cm 3It is a flat aluminum powder consisting of. Therefore, when using flat aluminum powder, the weight of the aggregate of flat aluminum powder is less than one-third of the weight of the methanol dispersion of the organometallic compound. On the other hand, the density of aluminum is 3.4 times the density of methanol. Therefore, the volume ratio of the methanol dispersion of the organometallic compound is greater than the volume ratio consisting of the theoretically calculated volume from the weight of the aggregate of flat aluminum powder. Therefore, when the aggregate of flat aluminum powder is stirred in a methanol dispersion of the organometallic compound with a large volume ratio, the flat aluminum powder disperses well in the low-density, low-viscosity methanol dispersion of the organometallic compound and is mixed evenly in the methanol dispersion. In this way, the collection of flat powders is weighed at a weight less than the weight obtained by multiplying the weight of methanol by the ratio of the density of the flat powder used to the density of the methanol, and the weighed collection of flat powders is put into a methanol dispersion of an organometallic compound.When the collection of flat powders is stirred in the methanol dispersion of an organometallic compound, because the volume ratio of the methanol dispersion of an organometallic compound is large, all of the flat powders are well dispersed in the low-viscosity, low-density methanol dispersion of an organometallic compound regardless of the density of the flat powders, and are mixed evenly in the methanol dispersion, so that all of the flat powders are covered with the methanol dispersion of an organometallic compound. In the third process, a homogenizer is placed in the container and operated within the container. At this time, since the methanol dispersion of the organometallic compound is a liquid with low viscosity and low density, the shock waves generated by the homogenizer are consumed at a low rate when exciting the methanol dispersion, and the shock waves are efficiently and repeatedly applied to the collection of flat powders via the methanol dispersion. As a result, shock waves are repeatedly applied to all the flat powders via the methanol dispersion of the organometallic compound. On the other hand, even for flat powders that have a relatively high density, an extremely thick flat powder, and the largest flat powder size, i.e., a density of 7.8 g / cm 3 The weight of a single flat piece of reduced iron powder with a particle size of 100 μm and a thickness of 15 μm is only 1×10 -6Therefore, even if the flat powder has flat surfaces that overlap each other in a complex manner, shock waves are repeatedly applied to the extremely lightweight flat powder, causing the overlapping flat surfaces to separate into individual flat particles, which are then covered with a methanol dispersion of the organometallic compound. In other words, flat powders have flat surfaces with a large aspect ratio, which is the ratio of the average major axis and minor axis to the thickness. Furthermore, even flat powders of the same type have variations in the size and thickness of the flat surfaces. When such flat powder clusters are handled in an air atmosphere, the flat surfaces overlap in a complex manner. On the other hand, when flat powders with directly overlapping flat surfaces are used to form a sheet from the cluster of flat powders, the flat powders with directly overlapping flat surfaces form areas in the sheet that have weak mechanical strength. Furthermore, if all overlapping flat powders could be separated into individual flat powder sheets, the amount of flat powder used to form the sheet would be reduced. Therefore, a process is required to reliably separate flat powders with overlapping flat surfaces. On the other hand, when attempting to separate flat powders with overlapping flat surfaces in an air atmosphere, frictional forces are generated between the overlapping flat surfaces, making separation difficult. Furthermore, it is difficult to determine whether the flat surfaces overlap. In contrast, the methanol dispersion of the organometallic compound is a low-viscosity, low-density liquid. Furthermore, as described above, the volume ratio of the methanol dispersion of the organometallic compound is greater than the volume ratio theoretically calculated from the weight of the flat powder cluster. Therefore, when the flat powder cluster is stirred in the methanol dispersion of the organometallic compound, the flat powder cluster is well dispersed in the methanol dispersion of the organometallic compound and evenly mixed with the methanol dispersion, regardless of the density, thickness, or size of the flat powder cluster. When shock waves are repeatedly generated in this mixture using a homogenizer, the shock waves spread throughout the methanol dispersion of the organometallic compound. The shock waves are then efficiently and repeatedly applied to the flat powder clusters, even at the overlapping areas of the flat powder clusters. Because the flat powder clusters are extremely lightweight, the overlapping flat powder clusters are easily separated. As a result, the overlapping flat powder clusters are reliably separated into individual flat powder clusters. Furthermore, when an ultrasonic homogenizer is used, the generation and disappearance of a huge number of bubbles, each two orders of magnitude smaller than the flat surfaces of the powder, is repeated in the methanol dispersion of the organometallic compound (this phenomenon is called cavitation). When the bubbles burst, shock waves are generated continuously throughout the entire methanol dispersion of the organometallic compound, and the flat powder particles, whose flat surfaces overlap, are separated into individual flat particles in a short period of time. As a result, all of the flat powder particles are covered with the methanol dispersion of the organometallic compound. After this, the homogenizer is removed from the container. In the fourth process, the container is impact Acceleration is repeatedly applied, and finally, impact Acceleration is applied. In other words, by processing using a homogenizer device, all the flat powder is covered with a low viscosity, low density methanol dispersion of organometallic compounds and dispersed in the methanol dispersion. This mixture is subjected to three directions. impact When acceleration is applied, a low-viscosity, low-density dispersion of organometallic compounds in methanol disperses into flat particles. impact The powder is repeatedly moved in the direction of acceleration. At this time, since the flat powder has a flat surface with a large aspect ratio, the flat surface is placed on top together with a methanol dispersion of an organometallic compound. impactThe particles move repeatedly in the direction of acceleration. In addition, the phenomenon of the flat powder particles rearranging and overlapping with the flat surface facing up progresses in the methanol dispersion of the organometallic compound. As a result, a collection of flat powder particles overlapping with each other via the methanol dispersion of the organometallic compound spreads over the entire bottom surface of the container. Finally, the particles move in the vertical direction. impact Acceleration is applied, and the vibration of the container is stopped. As a result, the collection of flat powder particles, with their flat surfaces overlapping each other via the methanol dispersion of the organometallic compound, spreads across the entire bottom surface of the container and forms the shape of the bottom surface of the container. In the fifth treatment, the container is heated to the boiling point of methanol. Consists of size Clusters of fine crystals of organometallic compounds are deposited in the gaps between the overlapping flat surfaces of the flat powder and on the entire surface of the cluster of flat powder. In other words, in the methanol dispersion of organometallic compounds, the organometallic compounds are dispersed in the methanol in a molecular state, so when the methanol is evaporated, the organometallic compounds before dispersion are dispersed into particles smaller than 100 nm. Consists of size The organometallic compound precipitates as a cluster of fine crystals. Because the concentration of the organometallic compound in the methanol dispersion is low and the volume ratio of the organometallic compound in the methanol dispersion is greater than the volume theoretically calculated from the weight of the cluster of flat powder, when the excess methanol evaporates, the thickness of the cluster of fine crystals precipitated between the flat surfaces and on the surface of the cluster of flat powder is thin, at submicron thickness. Because the organometallic compound, which was dispersed in a molecular state, precipitates as fine crystals, the fine crystals are a cluster of crystals consisting of an accumulation of crystals that form single molecules of the organometallic compound. Therefore, when stress is applied to the fine crystals, they easily break down. However, the finer the crystals, the more difficult it is to apply stress to them, and there is a limit to how fine the crystals can be. Furthermore, the evaporated methanol is recovered in a recovery machine and reused. In the sixth process, a plate covering the entire surface of the flat powder mass in the container is placed over the entire surface of the flat powder mass, and the entire surface of the plate is uniformly compressed. During this process, the gaps where the flat surfaces of the flat powder overlap and the clusters of fine crystals that have precipitated overlapping on the entire surface of the flat powder mass are crushed into finer crystals. Since relatively larger crystals are easier to crush, the relatively larger fine crystals are crushed first, and the crushing of the fine crystals progresses while the compressive load is applied. Meanwhile, as the fine crystals are crushed, new voids are formed in the cluster of fine crystals, and the crushed, finer crystals move into and fill the voids. As this crushing of the fine crystals progresses, the crushed, finer crystals overlap at high density in the gaps where the flat surfaces of the flat powder overlap and on the entire surface of the cluster of flat powder, and the clusters of finer crystals accumulate at high density, forming an extremely thin layer of crystals. When the crystals reach their limit of size, applying a compressive load to the plate material will not cause the fine crystals to break down, and the plate material to which the compressive load is applied will no longer move, resulting in an increase in the repulsive force from the plate material. At this point, the process of compressing the plate material surface is stopped. As a result, the size of the fine crystals is reduced to around 20 nm, which is nearly 1 / 5 of the size at the time of deposition. The thickness of the fine crystals of around 20 nm, which are piled up at a high deposition density between the flat surfaces and on the surface of the flat powder clusters, is 120-1 6 The thickness is approximately 20 nm. The compressive load applied to the plate is equivalent to 10-100 kg, depending on the size of the container and the amount of microcrystals. The impact acceleration applied to the container is 0.2-1.0 G, depending on the size of the container and the amount of microcrystals. As a result, clusters of organometallic compound crystals, each approximately 20 nm in size, are densely stacked in the gaps where the flat surfaces of the flat powder overlap, and on the entire surface of the cluster of flat powder. In the seventh process, a compressive load is applied evenly across the entire surface of the sheet, and the container is heated to the thermal decomposition temperature of the organometallic compound, causing the thermal decomposition of the organometallic compound microcrystals. First, moisture adsorbed on the flat powder and other foreign matter, such as compounds containing hydroxyl groups, vaporize. Next, the thermal decomposition of the organometallic compound microcrystals begins, and the organometallic compound thermally decomposes into organic molecules and metal or metal oxide molecules. When the organic molecules have completely evaporated, the metal or metal oxide molecules aggregate to form granular nanoparticles made of metal or metal oxide, approximately 10 nm in size. Six to eight of these granular nanoparticles overlap and precipitate simultaneously, forming a nanoparticle cluster with a thickness of 60 to 80 nm. The metal or metal oxide nanoparticles are free of impurities and precipitate as pure metal or metal oxide nanoparticles. Furthermore, because the metal nanoparticles precipitate as activated metal nanoparticles, adjacent metal nanoparticles form metallic bonds at their contact points. After this, the metal nanoparticles that have been metal-bonded are re-bonded by frictional heat. Meanwhile, as the thermal decomposition of the microcrystals progresses, foreign matter consisting of organic matter adsorbed to the flat powder vaporizes. This cleans the flat surfaces of the flat powder, and clusters of intrinsic metal or intrinsic metal oxide nanoparticles precipitate on the cleaned flat surfaces, increasing the bonding strength of the metal or metal oxide nanoparticles bonded to the flat surfaces by frictional heat. The bonding strength between intrinsic metal or metal oxide nanoparticles due to frictional heat also increases. Furthermore, because the granular metal or metal oxide nanoparticles are small, around 10 nm, and the contact area between the granular nanoparticles and the flat surfaces is extremely small, when the granular metal or metal oxide nanoparticles are bonded to the flat surfaces by frictional heat, the flat surfaces do not undergo plastic deformation, and no stress distortion occurs on the flat surfaces. Therefore, there is no need to anneal the sheets made of clusters of flat powder. In the eighth process, the container is impactAcceleration is applied and the sheet made of the flat powder aggregate is peeled off from the bottom of the container. As a result, a sheet made of the flat powder aggregate is obtained. The layer of nanoparticle aggregates formed on the surface of the flat powder aggregate and in the gaps between the flat particles is a very thin bonding layer with a thickness of 60-80 nm, equivalent to a collection of 6-8 nanoparticles. Furthermore, the size of the nanoparticles, which are around 10 nm in size, is more than two orders of magnitude smaller than the flat surface of the flat powder. For this reason, the properties of the flat powder dominate in the sheet made of the flat powder aggregate. The method of producing a sheet made of a collection of flat powder according to the present invention provides the following effects. First, the substance that bonds the flat surfaces of the flat powder is metal or metal oxide nanoparticles, and the raw material for the metal or metal oxide nanoparticles is liquefied as a methanol dispersion in which an organometallic compound is dispersed in methanol. Because this liquid has low viscosity and density, by continuously performing the second and third processes, it is possible to interpose the methanol dispersion of the organometallic compound in the gaps between the flat surfaces of the separated flat powder. This solves the first problem described in paragraph 16. Second, when a homogenizer is operated inside the container, the shock waves generated by the homogenizer are consumed only to excite the organometallic compound methanol dispersion due to its low viscosity and density, and most of the impact energy is efficiently and repeatedly transmitted to the cluster of flat powder particles. Because the flat powder is extremely lightweight, even complexly stacked flat powder particles are reliably separated into individual flat powder particles. The organometallic compound methanol dispersion contacts the surface of all flat powder particles, regardless of their material, shape, or particle size distribution. This solves the second problem described in paragraph 16. Furthermore, the surfaces of all flat powder particles are hydrophobic and do not react with the organometallic compound methanol dispersion, allowing the organometallic compound methanol dispersion to contact the surfaces of the flat powder particles. Third, the container has three directions: left and right, front and back, and top and bottom. Impact force Repeatedly add Impact forceAt this time, since the methanol dispersion of the organometallic compound has low viscosity and low density, the methanol dispersion of the organometallic compound is added together with the flat powder. impact The particles are repeatedly moved in three directions of acceleration, repeatedly rearranging so that the flat surfaces overlap each other in the methanol dispersion of the organometallic compound. This causes the flat powder to spread over the entire bottom surface of the container, and a collection of flat powder particles with overlapping flat surfaces formed on the bottom surface of the container via the methanol dispersion of the organometallic compound forms the shape of the bottom surface. This solves the third problem described in paragraph 16. Fourth, because the individual flake powders are stacked together with their flat surfaces interposed in a methanol dispersion of an organometallic compound, the larger the aspect ratio of the flake powder, the less flake powder is used. This means that even expensive flake powder can be used to inexpensively produce sheets made of stacked flake powders. Fifth, methanol is evaporated from the cluster of flat powders whose flat surfaces overlap each other via a methanol dispersion of an organometallic compound, precipitating clusters of fine crystals of the organometallic compound in the gaps between the flat surfaces and on the surface of the cluster of flat powders. Furthermore, the entire surface of the cluster of flat powders is evenly compressed. This crushes the fine crystals to approximately one-fifth their original size, and the crushed crystal clusters overlap and accumulate at a high precipitation density in the gaps between the flat surfaces and on the surface of the cluster of flat powders. These crushed fine crystals, approximately 20 nm in size, become the raw material for clusters of metal or metal oxide nanoparticles that connect the flat surfaces of the flat powders. This solves the fourth problem described in paragraph 16. Sixth, the entire surface of the flaky powder mass is heated while being uniformly compressed, causing the crushed microcrystals to thermally decompose. During this process, clusters of metal or metal oxide nanoparticles are deposited simultaneously in high density, overlapping each other, in the gaps between the flat surfaces and on the surface of the flaky powder mass. Furthermore, the entire surface of the flaky powder mass is uniformly compressed, and the clusters of metal or metal oxide nanoparticles deposited at high density are bonded to the flat surfaces by frictional heat, and the nanoparticles are also bonded to each other by frictional heat. In other words, because the clusters of metal or metal oxide nanoparticles are deposited in a high density, overlapping each other, the compressed nanoparticles have difficulty moving within the nanoparticle mass. Frictional heat is instantly generated at the contact points of the nanoparticles with the flat surfaces and at the contact points between the nanoparticles. The nanoparticles are bonded to the flat surfaces by the bonding force generated by the frictional heat, and the nanoparticles are also bonded to each other by the bonding force generated by the frictional heat. This solves the fifth and sixth problems described in paragraph 16, and all of the problems described in paragraph 16 are solved. Seventh, flat powders made of metals, alloys, metal oxides, or inorganic compounds other than tin and zinc can be used as flat powders when manufacturing sheets made of a collection of flat powders. In other words, the thermal decomposition temperature of organometallic compounds, which has the highest thermal decomposition temperature, is 330°C in air. Among soft metals, tin has a low melting point of 232°C and exhibits low-temperature brittleness at temperatures around -40°C. Zinc also exhibits low-temperature brittleness. In contrast, flat powders made of metals, alloys, metal oxides, or inorganic compounds other than tin and zinc have melting points above 330°C and do not exhibit low-temperature brittleness, making them suitable for use at extremely low temperatures. Therefore, sheets made of a collection of flat powders, with the flat surfaces of the powders bonded together, can be used in harsh environments such as high temperatures, extremely low temperatures, vacuums, and high pressures. Eighth, organometallic compounds precipitate metals or metal oxides made of various materials through thermal decomposition, so the nanoparticles that connect the flat surfaces of the flat powder can be made of a metal or metal oxide nanoparticle material that is most suitable for exhibiting the properties of the sheet made of an aggregate of flat powder. Ninth, sheets made of a collection of flat powder can be produced at low cost using inexpensive materials. That is, the organometallic compound and flat powder are general-purpose industrial materials, and only small amounts of the organometallic compound and flat powder are used. Furthermore, all eight processes for producing the sheet are extremely simple. Therefore, the cost of producing the sheet is low. As explained above, the sheet produced by this manufacturing method is made up of a collection of flat powders, with the flat surfaces of the separated flat powders joined together via clusters of metal or metal oxide nanoparticles, allowing for the production of a sheet made up of a collection of flat powders with revolutionary effects not found in conventional collections of flat powders.

[0020] The method for producing a sheet made of a collection of flat powder described in paragraph 18 is a method for producing a sheet made of a collection of soft magnetic flat powder, and the method for producing a sheet made of a collection of soft magnetic flat powder is as follows: The flat powder described in paragraph 18 is either iron, permalloy, silicon steel, sendust, or electromagnetic stainless steel. 1 type The organometallic compound described in paragraph 18 is nickel octylate, which precipitates nickel by thermal decomposition, and any of the above 1 type A method for producing a sheet consisting of a collection of soft magnetic flat powder, comprising using a soft magnetic flat powder made of the material as the flat powder described in paragraph 18, using the nickel octylate as the organometallic compound described in paragraph 18, and producing a sheet consisting of a collection of flat powder in which the flat surfaces of the soft magnetic flat powder are joined together via collections of nickel nanoparticles, according to the method for producing a sheet consisting of a collection of flat powder described in paragraph 18.

[0021] First, the properties of soft magnetic flat powders of iron, permalloy, silicon steel, sendust, or electromagnetic stainless steel will be explained. The soft magnetic flat powder made of iron and permalloy has a large initial relative permeability and a large maximum relative permeability, and the sheet made of a collection of flat powders in which the flat surfaces of the soft magnetic flat powder are bonded together with a collection of nanoparticles is effective as a sheet for shielding magnetism.In addition, the soft magnetic flat powder made of iron, permalloy, silicon steel, sendust, or electromagnetic stainless steel has a constant value in the imaginary part of the complex permeability in a specific frequency band, so the sheet made of a collection of flat powders in which the flat surfaces of these soft magnetic flat powders are bonded together with a collection of nanoparticles is effective as a sheet for absorbing electromagnetic wave noise or preventing electromagnetic noise interference in a specific frequency band. Here, we will explain about iron flake powder. Electromagnetic soft iron, which has magnetic properties similar to those of pure iron, has an initial relative permeability of 150 and a maximum relative permeability of 1×10 in a DC magnetic field. 4The relative permeability in a 100 kHz AC magnetic field is 100. Furthermore, the saturation magnetic flux density of electromagnetic soft iron is 2.2 Tesla, the highest among soft magnetic materials. Therefore, a sheet made by overlapping flat iron powder surfaces effectively functions as a shielding film. It is particularly effective as a magnetic shield for devices that generate strong magnetic fields, such as MRI (Magnetic Resonance Imaging) and power transformers. Iron, on the other hand, is a relatively hard metal, with a Vickers hardness of 110 Hv. Iron powder is divided into reduced iron powder and atomized iron powder. Reduced iron powder has many voids and is easier to flatten than atomized iron powder, but its high hardness makes it thicker. Therefore, reduced iron powder has a higher flatness ratio than atomized iron powder, and the imaginary part of its complex permeability has a consistent magnitude in the frequency range of 100 kHz to 10 MHz. Therefore, a sheet made of reduced iron powder flakes functions as a sheet for absorbing electromagnetic noise or preventing electromagnetic noise interference in the 100 kHz-10 MHz frequency band. The skin depth of reduced iron powder for 100 kHz electromagnetic waves is 50 μm. Therefore, reduced iron powder flakes exhibit excellent performance as a magnetic shield for devices that generate strong magnetic fields. They are also effective in a limited frequency band as a sheet for absorbing electromagnetic noise or preventing electromagnetic noise interference. Therefore, when reduced iron powder flakes are used as the metallic flake powder described in paragraph 17 and a sheet is formed by joining the flat surfaces of the reduced iron powder together according to the method described in paragraph 17, it can be used as a magnetic shielding sheet and a sheet for absorbing electromagnetic noise or preventing electromagnetic noise interference. In contrast, permalloy is a soft magnetic material made from an alloy with high magnetic permeability. The higher the magnetic permeability of the flat powder and the lower the magnetic resistance, the greater the magnetic shielding effect. Since magnetic resistance is inversely proportional to the magnetic permeability, a sheet made from flat powder of permalloy with high magnetic permeability has a high magnetic shielding effect. For example, permalloy with 45% nickel has an initial relative magnetic permeability of 2.5 x 10 in a DC magnetic field. 3 and the maximum relative permeability is 2.5×10 4However, its saturation magnetic flux density is 0.9 Tesla, which is smaller than that of soft magnetic iron. On the other hand, permalloy, which is made of 79% nickel and 4% molybdenum, has an initial relative permeability of 2×10 4 and the maximum relative permeability is 2×10 5 is extremely high. However, the higher the nickel content, the more expensive Permalloy becomes, so a nickel content of 50% or less is desirable. Therefore, a sheet made by overlapping flat surfaces of Permalloy powder becomes an excellent sheet for magnetic shielding. For this reason, sheets made of Permalloy flat powder are effective as magnetic shielding sheets in areas where external magnetic fields are relatively small, such as leakage magnetic fields from electrical equipment, AC magnetic fields from current transmission and distribution lines, urban magnetic noise, and environmental magnetic fields. According to Non-Patent Document 1, Permalloy flat powder containing 50% nickel has an aspect ratio of 38 and an average particle size of 14 μm. Furthermore, the imaginary part of the complex permeability rises sharply around 100 MHz, reaches a peak value of 8.8 at 3.3 GHz, decreases around 4 GHz, and reaches a value of 3.5 at 10 GHz. Therefore, this permalloy flake powder has an imaginary part of its complex permeability of 5 or greater in the 1-8 GHz frequency band, and a sheet made by overlapping flat surfaces of permalloy flake powder functions as a sheet for absorbing electromagnetic noise or preventing electromagnetic noise interference in this frequency band. Thus, a sheet made by overlapping flat surfaces of permalloy flake powder exhibits excellent performance as a magnetic shielding sheet in areas with relatively small external magnetic fields. It is also effective as a sheet for absorbing electromagnetic noise or preventing electromagnetic noise interference in a limited frequency band. Therefore, when permalloy flake powder is used as the flat powder made of the alloy described in paragraph 17 and a sheet made of flat powder particles joined together according to the method described in paragraph 17 is formed, it can be used as a magnetic shielding sheet, or a sheet for absorbing electromagnetic noise or preventing electromagnetic noise interference. On the other hand, soft magnetic alloy materials include silicon steel (iron with a small amount of silicon), Permalloy (iron with nickel), Sendust (iron with silicon and aluminum), Permendur (iron with cobalt), and electromagnetic stainless steel (iron with chromium and silicon). Among these, silicon steel becomes brittle with increasing silicon content, and flattening is possible only with silicon content below 10%. Even slight variations in silicon content significantly affect the permeability characteristics of silicon steel. Furthermore, the manufacturing cost of Permalloy increases with increasing nickel content, but low nickel content reduces permeability, so it is desirable to limit the nickel content to around 50%. Sendust is hard and brittle, but adding a small amount of nickel and reducing the silicon content makes it possible to flatten it. Furthermore, Permendur, being an alloy with cobalt, is expensive to manufacture and therefore unsuitable as flattening powder for use in sheets that absorb electromagnetic noise or prevent electromagnetic noise interference. Furthermore, adding aluminum to electromagnetic stainless steel makes it easier to flatten. Therefore, the four alloys, excluding Permendur, can be used as soft magnetic flat powder. The thickness of flat powders made from the four alloys is within the range of 1-1.5 μm. In contrast, because the hardness of reduced iron powder is higher than that of the four alloys, the thickness of flat powders made from reduced iron powder is as thick as 10-20 μm. On the other hand, as explained in paragraph 16, the greater the flatness of the flat powder, the greater the imaginary part of the complex permeability. Furthermore, as shown in Equation 1 in paragraph 3, electromagnetic noise absorption depends on the magnitude of the imaginary part of the flat powder's complex permeability and its electrical conductivity. Therefore, sheets used for electromagnetic noise absorption or interference prevention can be made using flat silicon steel powder with less than 10% silicon content, flat permalloy powder with nearly 50% nickel content, flat sendust powder with a small amount of nickel and reduced silicon content, and flat electromagnetic stainless steel powder with aluminum content. However, the complex permeability of flat powders made from these four alloys changes with slight changes in the composition of elements other than iron. Furthermore, because the hardness of the four alloys differs, the flatness of the flat powder differs for each of the four alloys, and the magnitude of the imaginary part of the complex permeability also differs for each of the four alloys. Furthermore, the frequency characteristics of the imaginary part of the complex magnetic permeability differ significantly among the four types of alloys, and even within the same type of alloy, they differ depending on the components other than iron. Therefore, when creating a sheet made of an assembly of alloy flat powders to be used for absorbing electromagnetic noise or preventing electromagnetic noise interference, the characteristics of the imaginary part of the complex magnetic permeability of the alloy soft magnetic flat powder can be utilized by using different alloy soft magnetic flat powders depending on the frequency band of the electromagnetic waves to be absorbed. Therefore, by using the alloy soft magnetic flat powder as the alloy flat powder described in paragraph 18 and forming a sheet made of an assembly of flat powders by bonding the flat surfaces of the flat powders together according to the method described in paragraph 18, the sheet can be used to absorb electromagnetic noise or prevent electromagnetic noise interference. Incidentally, the hardness of soft magnetic flat powders varies, so the thickness of the flat powder varies depending on the material. For example, the thickness of flattened powder obtained by flattening reduced iron powder, which is hard and difficult to flatten, is as thick as 10-20 μm. In contrast, the thickness of flattened powder obtained by adding a small amount of nickel to sendust, a ternary alloy consisting of iron, silicon, and aluminum, and reducing the amount of silicon added, making flattening easier, is as thin as 1-1.5 μm. Furthermore, the weight of flattened powder varies greatly depending on the particle size and density of the flattened powder, as well as the thickness. For example, the weight of flattened reduced iron powder with a particle size of 100 μm and a thickness of 15 μm is 0.927 × 10 -6In contrast, the weight of Sendust flat powder with a particle size of 40 μm and a thickness of 1 μm is 0.86 × 10 -8 It is even lighter at 7.8g. The density of iron is 7.8g / cm 3 The density of sendust is 7.6 g / cm 3 The densities of both are similar. Therefore, the reason why the weight of the flat powder of reduced iron powder is two orders of magnitude larger than that of the flat powder of Sendust is due to the difference in the thickness and particle size of the flat powder. However, the weight of one piece of soft magnetic flat powder is extremely small, even for flat powder of reduced iron powder. The density of soft magnetic flat powder made of metal or alloy is 7.7-8.3g / cm 3 is within the range. Meanwhile, in the method for manufacturing a sheet consisting of an aggregate of flat powder in which the flat surfaces of the flat powder are bonded together via an aggregate of nanoparticles as described in paragraph 18, the aggregate of flat powder is weighed to a weight less than the weight obtained by multiplying the weight of methanol by the ratio of the density of the flat powder used to the density of the methanol, and the weighed aggregate of flat powder is mixed with a low-viscosity, low-density methanol dispersion of an organic compound, and a homogenizer is operated in the mixture. When the homogenizer is operated in the mixture, because the methanol dispersion of the organometallic compound is a low-viscosity, low-density liquid, the shock waves generated by the homogenizer are efficiently and repeatedly applied to the aggregate of soft magnetic flat powder through the methanol dispersion without substantially exciting the methanol dispersion. Because each sheet of soft magnetic flat powder is extremely light, even if the weight, thickness, size, and density of the soft magnetic flat powder vary, the overlapping soft magnetic flat powder can be easily separated into individual sheets of flat powder via the methanol dispersion of the organometallic compound, and the separated soft magnetic flat powder is covered with the methanol dispersion of the organometallic compound. After this, the container is impact Acceleration is repeatedly applied, and finally, impact Acceleration was applied. Through the treatment using the homogenizer device, all of the soft magnetic flaky powder was covered with the low-viscosity, low-density methanol dispersion of the organometallic compound and dispersed in the methanol dispersion. impactWhen acceleration is applied, the methanol dispersion of the organometallic compound is low in viscosity and density, and each sheet of soft magnetic flaky powder is extremely light. Therefore, even if the weight, thickness, size, and density of the soft magnetic flaky powder are different, the methanol dispersion of the organometallic compound disperses along with the soft magnetic flaky powder. impact At this time, the soft magnetic flaky powder moves in the direction of acceleration, with the flat surface facing up because it has a large aspect ratio. impact The flat powder is repeatedly moved in the direction of acceleration, and the flat surfaces are rearranged and overlapped with each other, with the flat surfaces facing up, in the methanol dispersion of the organometallic compound. As a result, even if the weight, thickness, size, and density of the soft magnetic flat powder are different, the collection of flat powder with the flat surfaces overlapping each other through the methanol dispersion of the organometallic compound spreads across the entire bottom surface of the container. Therefore, there are no restrictions on the material, thickness, size, particle size distribution, or hardness of the soft magnetic flat powder used. Next, we will explain the nano-sized material that bonds the flat surfaces of the soft magnetic flat powders made from either iron, permalloy, silicon steel, sendust, or electromagnetic stainless steel. As explained in paragraph 18, the thickness of the layer of nano-sized material that bonds the flat surfaces of the flat powders is thin, at 60-80 nm. Furthermore, nanoparticles with a size of approximately 10 nm are more than two orders of magnitude smaller than the area of ​​the flat surfaces of the soft magnetic flat powder. Therefore, a sheet in which the flat surfaces of the soft magnetic flat powders are bonded together with a collection of nanoparticles will have the properties of the soft magnetic flat powder. However, if the material of the nanoparticles is a ferromagnetic material with soft magnetic properties, it will not impair the soft magnetic properties of the sheet made from the collection of soft magnetic flat powders. Nickel is one such ferromagnetic material. Nickel has a maximum relative magnetic permeability of 600. In addition, its complex permeability at 2.45 GHz and 50°C has a real part of 1.592 and an imaginary part of 1.349. Therefore, nickel is a ferromagnetic material among metals and metal oxides, with both the maximum relative magnetic permeability and complex permeability having constant values. Its maximum relative magnetic permeability is 1 x 10 4 On the other hand, nickel has an electrical resistance of 69.3×10 -9 100 x 10 of the electrical resistivity of iron in Ω m-9 Because nickel has a lower resistance than iron (Ω·m), it exhibits greater electromagnetic wave reflection and absorption losses than iron, making it effective for electromagnetic wave shielding. Furthermore, its complex permeability remains constant throughout the high-frequency range, providing a certain level of magnetic shielding and electromagnetic noise absorption. Nickel's Vickers hardness is 400-500 HV, higher than that of PB Permalloy, the softest soft magnetic material (120-160 HV). However, nickel nanoparticles are small (approximately 10 nm), and the contact area they form with the flat surface of Permalloy powder is extremely small. Therefore, when a cluster of nickel nanoparticles comes into contact with the flat surface of Permalloy, the tiny contact area on the Permalloy flat surface undergoes slight elastic deformation, preventing stress distortion on the Permalloy flat surface. The frictional heat generated at the tiny contact point between the two bonds the nickel nanoparticles to the Permalloy flat surface. Based on this idea, we decided to bond the flat surfaces of the soft magnetic flat powder with a cluster of nickel nanoparticles. Here, we will explain a method for producing a sheet made of a collection of flat soft magnetic powder, in which the flat surfaces of the powder are joined together via a collection of nickel nanoparticles, in accordance with the eight processes described in paragraph 18. In the first process, nickel octylate is dispersed in methanol up to a maximum of 10% by weight to prepare a methanol dispersion of nickel octylate, and the methanol dispersion is filled into a container. In the second process, a collection of soft magnetic flat powder made of any of iron, permalloy, silicon steel, sendust, or electromagnetic stainless steel is weighed out to a weight less than the weight obtained by multiplying the weight of methanol by the ratio of the density of the flat powder used to the density of the methanol, and the collection of flat powder is poured into a container and the soft magnetic flat powder is stirred. In the third process, a homogenizer is placed in the container and operated within the container. In the fourth process, a homogenizer is placed in the container in three directions. impact Acceleration is repeatedly applied, and finally, impact By carrying out these four processes in succession, a cluster of flat powder particles, with the flat surfaces of the flat powder overlapping each other, is formed on the bottom surface of the container through the methanol dispersion of nickel octylate. In the fifth step, the temperature of the container is raised to the boiling point of methanol. In the sixth step, a plate that covers the entire surface of the flat powder collection in the container is placed over the entire surface of the flat powder collection, and the entire surface of the plate is evenly compressed to crush the fine nickel octylate crystals into even finer crystals. As a result, the even finer nickel octylate crystals are piled up and accumulated at a high density in the gaps where the flat surfaces of the flat powder overlap and over the entire surface of the flat powder collection. In the seventh process, a compressive load is evenly applied to the surface of the plate material, and the container is heated to 290°C, at which point the thermal decomposition of nickel octylate is completed, causing the nickel octylate to thermally decompose. In the eighth process, the container is rotated in three directions: front and back, left and right, and top and bottom. impact Acceleration is applied and the sheet consisting of the collection of flat powder is peeled off from the bottom of the container. As a result, a sheet consisting of a collection of flat powder is obtained, with the flat surfaces of the flat powder bonded together via a collection of nickel nanoparticles approximately 10 nm in size that are bonded by frictional heat. The thermal decomposition temperature of nickel octoate in a nitrogen atmosphere is 340°C, 50°C higher than in air. Here, we will explain the phenomena that occur during the eight processes and the effects that each process brings about. In the first process, nickel octylate is dispersed in methanol, whereby the nickel octylate becomes molecular and disperses in the methanol. This results in the raw material for nickel nanoparticles being in a liquid phase. Note that because nickel octylate does not dissolve in methanol, when the methanol is evaporated from the nickel octylate, fine crystals of nickel octylate are precipitated. In the second process, a mass of soft magnetic flaky powder made of either iron, permalloy, silicon steel, sendust, or electromagnetic stainless steel is weighed out to a weight less than the weight of methanol multiplied by the ratio of the density of the flaky powder used to the density of the methanol, and the mass of soft magnetic flaky powder is placed in a container and stirred. Meanwhile, since the hardness of soft magnetic flaky powder varies depending on the material, the thickness of the flattened powder also varies depending on the material. Reduced iron powder, which is the hardest of all soft magnetic flaky powders and difficult to flatten, is flattened to a thickness of 10-20 μm. The weight of flattened reduced iron powder with a particle size of 100 μm and a thickness of 15 μm is 0.927 × 10 -6 g. In contrast, Sendust, a ternary alloy consisting of iron, silicon, and aluminum, is made by adding a small amount of nickel and reducing the amount of silicon added, making flattening easier. The thickness of the flattened powder is as thin as 1-1.5 μm. Sendust flattened powder with a particle size of 40 μm and a thickness of 1 μm weighs 0.86×10 -8 g. The density of iron is 7.8 g / cm 3 The density of sendust is 7.6 g / cm 3 The reason why the weight of the flat powder of reduced iron powder is two orders of magnitude larger than that of Sendust is due to the difference in the thickness and particle size of the flat powder. On the other hand, the density of methanol is 0.792 g / cm 3 The density of nickel octylate is 1.08 g / cm 3Therefore, the density of the nickel octylate methanol dispersion is nearly 1 / 10 of the density of the soft magnetic flaky powder. Therefore, the weight of the soft magnetic flaky powder used is less than 10 times the weight of the methanol in which the nickel octylate is dispersed. On the other hand, the density of the nickel octylate methanol dispersion is nearly 1 / 10 of the density of the soft magnetic flaky powder. Therefore, the theoretical volume calculated from the weight and density of the soft magnetic powder mass is less than the volume of the nickel octylate methanol dispersion. However, the weight of a single sheet of soft magnetic flaky powder is extremely small. Furthermore, the concentration of the nickel octylate methanol dispersion is low, at around 10% by weight. Therefore, the viscosity of the nickel octylate methanol dispersion is close to that of methanol. The viscosity of methanol is extremely low, at 0.59 mPa·sec. Therefore, if a collection of soft magnetic flat powder is weighed out to a weight less than 1 / 10 of the weight of the methanol and mixed with a methanol dispersion of nickel octylate, and the collection of soft magnetic flat powder is stirred in the methanol dispersion of nickel octylate, the weight of a single piece of soft magnetic flat powder is extremely small, so the soft magnetic flat powder disperses well in the low-density, low-viscosity methanol dispersion of nickel octylate, and the soft magnetic flat powder is mixed evenly in the methanol dispersion. As a result, even if the weight, thickness, size, and density of the soft magnetic flat powder differ, all of the soft magnetic flat powder is covered with the methanol dispersion of nickel octylate. In the third process, a homogenizer is placed in the container and operated within the container. At this time, since the methanol dispersion of nickel octylate is a low-viscosity, low-density liquid, the proportion of the shock waves generated by the homogenizer that are consumed when exciting the methanol dispersion is small, and the shock waves are efficiently and repeatedly applied to the collection of soft magnetic flat powder via the methanol dispersion. As a result, shock waves are repeatedly applied to all of the soft magnetic flat powder via the methanol dispersion of nickel octylate. On the other hand, 3 Even if the particle size is as large as 100 μm and the thickness is as extremely thick as 15 μm, the weight of the flat powder of reduced iron powder is only 1 × 10 -6Therefore, even if the flat surfaces of the soft magnetic flat powder are intricately overlapping, shock waves are repeatedly applied to the extremely lightweight soft magnetic flat powder, causing the overlapping flat surfaces to separate into individual flat particles, which are then covered with a methanol dispersion of nickel octylate. In the fourth process, the container is impact Acceleration is repeatedly applied, and finally, impact Acceleration is applied. In other words, the soft magnetic flat powder that is piled up on the flat surface is separated into individual soft magnetic flat powders by processing using a homogenizer device, and all of the soft magnetic flat powders are covered with a low viscosity, low density methanol dispersion of nickel octylate, and are evenly dispersed in the methanol dispersion. This collection of soft magnetic flat powders is subjected to three directions of acceleration. impact When acceleration is applied repeatedly, the soft magnetic flaky powder is extremely light, so the low viscosity and low density methanol dispersion of nickel octylate dissolves in the flaky powder. impact The soft magnetic powder is repeatedly moved in the direction of acceleration. Since the soft magnetic powder has a flat surface with a large aspect ratio, the flat surface is placed facing up together with a methanol dispersion of nickel octylate. impact It moves repeatedly in the direction of acceleration. When the soft magnetic flat powder repeatedly moves in the methanol dispersion of nickel octylate, the flat powder particles rearrange with the flat surfaces facing up and overlap, a phenomenon that progresses in the methanol dispersion of nickel octylate. In this way, the flat surfaces of the soft magnetic flat powder overlap each other through the methanol dispersion of nickel octylate. As a result, the collection of flat powder particles with overlapping flat surfaces spreads across the entire bottom surface of the container as the shape of the bottom surface through the methanol dispersion of nickel octylate. Finally, impact Acceleration is applied to the container. Application of impact force Stop. In the fifth treatment, the container is heated to the boiling point of methanol. Consists of sizeClusters of fine crystals of nickel octylate are deposited in the gaps between the overlapping flat surfaces of the soft magnetic flaky powder and on the entire surface of the clusters of soft magnetic flaky powder. In other words, in the methanol dispersion of nickel octylate, nickel octylate is dispersed in the methanol in a molecular state, so when the methanol is evaporated, the nickel octylate before dispersion is dispersed into particles smaller than 100 nm. Consists of size It precipitates as a collection of fine crystals. Note that the concentration of nickel octylate in the methanol dispersion of nickel octylate is low, causing excess methanol to evaporate. At this time, the thickness of the fine crystals that precipitate in the gaps between the flat surfaces and on the surfaces of the flat powder clusters is thin, at submicron thickness. Meanwhile, because the nickel octylate, which was dispersed in a molecular state, precipitates as fine crystals, the fine crystals are a collection of crystals that form single molecules of nickel octylate. Therefore, when stress is applied to the fine crystals, they easily break down. However, the finer the crystals, the more difficult it is to apply stress to them, and there is a limit to how fine they can be. Furthermore, the evaporated methanol is recovered in a recovery machine and reused. In the sixth process, a plate covering the entire surface of the soft magnetic flat powder mass in the container is placed over the entire surface of the soft magnetic flat powder mass, and the entire surface of the plate is uniformly compressed. During this process, the gaps between the overlapping flat surfaces of the soft magnetic flat powder mass and the clusters of nickel octylate fine crystals that have been deposited overlapping on the entire surface of the soft magnetic flat powder mass are crushed into finer crystals. Since relatively larger crystals are more easily crushed, the relatively larger fine crystals are crushed first, and the crushing of the fine crystals progresses while the compressive load is applied. Meanwhile, as the fine crystals are crushed, new voids are formed in the cluster of fine crystals, and the crushed, finer clusters of crystals move into the voids and fill them. As the fine crystals are crushed, the crushed, finer crystals are densely packed together in the gaps between the overlapping flat surfaces of the soft magnetic powder and on the entire surface of the soft magnetic powder aggregates. The finer crystals then accumulate at high density, forming a thin layer. When the nickel octoate crystals reach their limit, applying a compressive load to the plate material no longer breaks the fine crystals, and the plate material no longer moves when the compressive load is applied, resulting in an increase in the repulsive force from the plate material. At this point, the compression process on the plate material surface is stopped. As a result, the size of the fine crystals is reduced to approximately 20 nm, nearly one-fifth of their initial size. The thickness of the nickel octoate fine crystals, approximately 20 nm in size and stacked at high density between the soft magnetic flat surfaces and on the surface of the soft magnetic powder aggregates, reaches 120-180 nm. The compressive load applied to the plate material is equivalent to 10-100 kg, depending on the size of the container and the amount of microcrystals. The impact acceleration applied to the container is 0.2-1.0 G, depending on the size of the container and the amount of microcrystals. This causes clusters of nickel octylate crystals, each about 20 nm in size, to overlap at high density in the gaps between the overlapping flat surfaces of the soft magnetic flaky powder and on the entire surface of the clusters of flat powder. In the seventh process, a compressive load is applied evenly across the entire surface of the plate, and the container is heated to 290°C, at which point the thermal decomposition of the nickel octylate is complete. This thermal decomposition occurs when the moisture and hydroxyl-containing compounds adsorbed to the flat powder vaporize. Next, the thermal decomposition of the nickel octylate microcrystals begins, and the nickel octylate decomposes into octylic acid and nickel. When the vaporization of the octylic acid molecules is complete, the nickel molecules aggregate to form granular nickel nanoparticles approximately 10 nm in size. Six to eight of these granular nickel nanoparticles then precipitate simultaneously, overlapping each other. The nickel nanoparticles are free of impurities and precipitate as pure nickel nanoparticles. Furthermore, the nickel nanoparticles precipitate as activated nanoparticles. Therefore, adjacent nickel nanoparticles form metallic bonds at the contact points. The metallically bonded nickel nanoparticles are then rejoined by frictional heat. Meanwhile, as the thermal decomposition of the nickel octylate microcrystals progresses, the organic foreign matter adsorbed to the soft magnetic flat powder vaporizes. This cleans the flat surfaces of the soft magnetic flat powder, and clusters of genuine nickel nanoparticles precipitate on the cleaned flat surfaces, increasing the bonding strength of the nickel nanoparticles that bond to the flat surfaces through frictional heat. The bonding strength between the genuine nickel nanoparticles due to frictional heat also increases. Furthermore, because the nickel nanoparticles are small, around 10 nm, and the contact area between the granular nanoparticles and the flat surfaces is extremely small, no stress distortion occurs on the flat surfaces when the nickel granular nanoparticles bond to the flat surfaces through frictional heat. Therefore, there is no need to anneal the sheets made of clusters of soft magnetic flat powder for stress relief. In the eighth process, the container is impactAcceleration is applied and the sheet consisting of the soft magnetic flaky powder is peeled off from the bottom of the container. This results in a sheet consisting of the soft magnetic flaky powder. The layer of nickel nanoparticles formed on the surface of the flaky powder and in the gaps between the particles is a very thin layer with a thickness of 60-80 nm, equivalent to a collection of 6-8 nanoparticles. Furthermore, the size of the nickel nanoparticles, which are around 10 nm in size, is more than two orders of magnitude smaller than the flat surface of the flaky powder. For this reason, the properties of the soft magnetic flaky powder dominate in the sheet consisting of the soft magnetic flaky powder. Here, when soft magnetic flat powder is used as the flat powder described in paragraph 18, nickel octylate is used as the organometallic compound described in paragraph 18, and the flat surfaces of the soft magnetic flat powder are joined together via clusters of nickel nanoparticles according to the method described in paragraph 18, a sheet consisting of a collection of soft magnetic flat powder has the following effects. First, the material that bonds the flat surfaces of the soft magnetic flaky powder is a cluster of nickel nanoparticles, and then nickel octylate, the raw material for the nickel nanoparticles, is dispersed in methanol to create a liquid phase. Because this liquid has low viscosity and density, by continuously performing the second and third processes, it becomes possible to interpose the methanol dispersion of nickel octylate in the gaps between the flat surfaces of the soft magnetic flaky powder that have been separated into individual pieces. Second, when a homogenizer is operated inside the container, the shock waves generated by the homogenizer are consumed only to excite the nickel octylate methanol dispersion due to its low viscosity and density, and most of the impact energy is efficiently and repeatedly transmitted to the soft magnetic flaky powder particles. Therefore, even if the soft magnetic flaky powder particles have complex overlapping flat surfaces, they are extremely lightweight and reliably separated into individual flat particles. Regardless of the material, shape, or particle size distribution of the flat powder particles, the nickel octylate methanol dispersion comes into contact with the surface of all the flat powder particles. Furthermore, the surfaces of all soft magnetic flaky powder particles are hydrophobic and do not react with the nickel octylate methanol dispersion, allowing the nickel octylate methanol dispersion to come into contact with the surface of the soft magnetic flaky powder. Third, the container has three directions: left and right, front and back, and top and bottom. Impact force Repeatedly add Impact force At this time, since the methanol dispersion of nickel octylate has low viscosity and low density and the soft magnetic flaky powder is extremely light, the methanol dispersion of nickel octylate is mixed with the soft magnetic flaky powder. impact The object is repeatedly moved in the direction of acceleration. This causes the soft magnetic flat powder to rearrange and overlap with the flat surfaces facing up in the methanol dispersion of nickel octylate. As a result, the soft magnetic flat powder spreads over the entire bottom surface of the container, and a collection of flat powder with flat surfaces overlapping each other is formed on the bottom surface of the container through the methanol dispersion of nickel octylate, forming the shape of the bottom surface. Fourth, because the individual soft magnetic flake powders are stacked flat-surface-to-flat surface via a methanol dispersion of nickel octylate, the larger the aspect ratio of the soft magnetic flake powder, the less soft magnetic flake powder is used. Therefore, even if the soft magnetic flake powder is expensive, a sheet consisting of a collection of soft magnetic flake powders stacked flat-surface-to-flat surface can be produced inexpensively. Fifth, methanol is evaporated from the clusters of flat powder whose flat surfaces overlap each other via a methanol dispersion of nickel octylate, precipitating clusters of nickel octylate microcrystals in the gaps between the flat surfaces and on the surface of the clusters of flat powder. Furthermore, the entire surface of the clusters of soft magnetic flat powder is evenly compressed. This crushes the microcrystals to about one-fifth their original size, and the crushed crystal clusters overlap and accumulate at high density in the gaps between the flat surfaces and on the surface of the clusters of flat powder. These crushed nickel octylate microcrystals, approximately 20 nm in size, become the raw material for clusters of nickel nanoparticles, approximately 10 nm in size, that connect the flat surfaces of the flat powder. Sixth, the soft magnetic flaky powder clusters are heated while being uniformly compressed, causing the crushed nickel octylate microcrystals to thermally decompose. During this process, clusters of nickel nanoparticles are deposited simultaneously in high density, overlapping each other, in the gaps between the flat surfaces and on the surfaces of the clusters of flat powder. Furthermore, the clusters of soft magnetic flaky powder are uniformly compressed, and the clusters of nickel nanoparticles deposited at high density are bonded to the flat surfaces by frictional heat, and the nickel nanoparticles are also bonded to each other by frictional heat. In other words, because the clusters of nickel nanoparticles are deposited overlapping each other at high density, it becomes difficult for the compressed nanoparticles to move within the clusters of nanoparticles. Frictional heat is generated at the contact points of the nanoparticles with the flat surfaces and at the contact points between the nanoparticles. The bonding force generated by the frictional heat bonds the nickel nanoparticles to the flat surfaces, and the bonding force generated by the frictional heat also bonds the nickel nanoparticles to each other. Seventh, soft magnetic flat powders made of iron, permalloy, silicon steel, sendust, or electromagnetic stainless steel can be used as flat powders to manufacture sheets made of a collection of flat powders. In other words, the thermal decomposition temperature of nickel octylate is 290°C in air. On the other hand, the melting points of soft magnetic flat powders made of iron, permalloy, silicon steel, sendust, or electromagnetic stainless steel are significantly higher than 290°C. Furthermore, none of these soft magnetic flat powders exhibit low-temperature brittleness, making them suitable for use at extremely low temperatures. Therefore, sheets made of a collection of flat powders in which the flat surfaces of the soft magnetic flat powders are bonded together can be used in harsh environments such as high temperatures, extremely low temperatures, vacuum, and high pressure. The thermal decomposition temperature of nickel octylate in a nitrogen atmosphere is 340°C, 50°C higher than in air, but significantly lower than the melting point of the soft magnetic flat powder. Eighth, the flat surfaces of the soft magnetic flake powder were bonded together with a cluster of nickel nanoparticles. Nickel has a maximum relative magnetic permeability of 600. Its complex permeability is 1.592 real and 1.349 imaginary at 2.45 GHz. Therefore, nickel is a ferromagnetic material among metals and metal oxides, with both its maximum relative magnetic permeability and complex permeability remaining constant. While its magnetic shielding performance is inferior to that of iron, its complex permeability remains constant in the high-frequency band. Therefore, the nickel nanoparticles do not impair the permeability characteristics of the soft magnetic flake powder in a sheet in which the flat surfaces of the soft magnetic flake powder are bonded together. Ninth, nickel octylate is a general-purpose industrial chemical. Furthermore, since the flat surfaces of the flat powder are bonded together, only a small amount of flat powder is required. Furthermore, all eight processes for bonding the flat surfaces together with a cluster of nickel nanoparticles are simple. Therefore, sheets made of a cluster of soft magnetic flat powder can be manufactured using inexpensive materials at low cost. As explained above, the sheet made from a collection of soft magnetic flat powder produced by this manufacturing method has flat surfaces joined together by collections of nickel nanoparticles, making it a sheet made from a collection of soft magnetic flat powder that has revolutionary effects not found in collections of conventional soft magnetic flat powder.

[0022] The method for producing a sheet made of an aggregate of soft magnetic flat powder described in paragraph 20 is a method for producing a sheet made of an aggregate of soft magnetic flat powder of multiple types of alloys, and the method for producing a sheet made of an aggregate of soft magnetic flat powder of multiple types of alloys is as follows: The soft magnetic flat powder described in paragraph 20 is a soft magnetic flat powder made of a plurality of alloys excluding iron described in paragraph 20, and the frequency characteristics of the imaginary part of the complex permeability of the soft magnetic flat powder made of the plurality of alloys are each Made of alloy The soft magnetic flat powders are different from each other, and each of the above Made of alloyA method for producing a sheet consisting of an assembly of soft magnetic flaky powders of multiple types of alloys, wherein the frequency characteristics of the imaginary part of the complex permeability of the soft magnetic flaky powder are such that the imaginary parts of the complex permeability complement each other in different frequency ranges, and the soft magnetic flaky powders consisting of multiple types of alloys are used as the flat powders described in paragraph 18, and nickel octylate described in paragraph 20 is used as the organometallic compound described in paragraph 18, and a sheet consisting of an assembly of flat powders of multiple types of alloys is produced according to the method for producing a sheet consisting of an assembly of flat powders described in paragraph 18, wherein the flat surfaces of the soft magnetic flaky powders of the multiple types of alloys are bonded to each other via clusters of nickel nanoparticles. 。

[0023] As described in paragraph 16, when soft magnetic powder is flattened in the plane direction, which is the direction of the easy axis of magnetization, the demagnetizing factor decreases, and the greater the flatness, the greater the imaginary part μ" of the complex permeability. In addition, the frequency characteristics of the imaginary part of the complex permeability of the flat soft magnetic powder vary greatly depending on the material of the flat soft magnetic powder. Therefore, if multiple types of soft magnetic flat powder made of metal or alloy have different frequency characteristics of the imaginary part of the complex permeability, and the frequency characteristics of the imaginary part of each complex permeability are complementary to each other in different frequency ranges, then if multiple types of soft magnetic flat powder made of such metal or alloy are used and the multiple types of flat powder are randomly joined together with their flat surfaces to form a sheet, the characteristics of the imaginary part of the complex permeability of the multiple types of flat powder will be reflected in the sheet, and the sheet will absorb electromagnetic noise over a wide frequency band. It will also serve as a sheet that prevents electromagnetic noise caused by electromagnetic waves interfering with each other. However, among the multiple types of soft magnetic flat powders made from metals or alloys, only the reduced iron powder has a higher hardness than the other soft magnetic flat powders, resulting in an extremely thick flat powder thickness of 10-20 μm. In contrast, the other soft magnetic flat powders are atomized or reduced soft magnetic powders whose compositions are finely adjusted to reduce hardness and enable flattening, resulting in a thickness deviation of 1-1.5 μm. Therefore, when a mixture of reduced iron powder and other flat powders is processed using the method described in paragraph 20, the flat surfaces of all the flat powders do not overlap with each other through the methanol dispersion of nickel octylate. Therefore, when producing a sheet using soft magnetic flat powders made from multiple types of metals or alloys, the reduced iron powder is excluded from the soft magnetic flat powders made from metals or alloys described in paragraph 20. Therefore, the multiple types of soft magnetic flat powders become multiple types of soft magnetic flat powders made from alloys. As a result, the multiple types of soft magnetic flat powder described in paragraph 20 can be combined to have three characteristics: first, flat powder made of multiple types of alloys excluding flat powder made of reduced iron powder; second, the frequency characteristics of the imaginary part of the complex permeability of the flat powder made of the multiple types of alloys are different from each other; and third, the frequency characteristics of the imaginary part of the complex permeability of each flat powder have frequency characteristics of the imaginary part of the complex permeability that complement each other in different frequency ranges. Furthermore, when the soft magnetic flat powder made of multiple types of alloys having these three characteristics is used as the soft magnetic flat powder described in paragraph 20 and subjected to the eight processes according to the method described in paragraphs 20-21, a sheet consisting of a collection of soft magnetic flat powder made of multiple types of alloys, with the flat surfaces randomly bonded together, can be produced. This sheet reflects the characteristics of the imaginary part of the complex permeability of soft magnetic flat powder made from multiple types of alloys with three characteristics, and because the imaginary part of the complex permeability has a constant magnitude over a wider frequency band that was difficult to achieve with a single type of flat powder, it is a sheet that can absorb electromagnetic noise over a wide frequency band or prevent electromagnetic noise interference, which was previously difficult to achieve. On the other hand, as described in paragraph 16, flat powder is produced by attriting atomized or reduced soft magnetic powder using a media agitation mill. Therefore, different materials for the flat powder affect the shape, structure, and hardness of the atomized or reduced soft magnetic powder, resulting in differences in not only the flatness but also the shape, particle size distribution, and hardness of the flat powder. However, as mentioned above, the thickness deviation is narrow (1-1.5 μm) and the thickness is thin. Furthermore, the method for producing a sheet made from a collection of soft magnetic flat powder consists of the eight processes described in paragraphs 20-21. On the other hand, even if the soft magnetic flat powder is made from multiple alloys (excluding reduced iron powder) and has different flatness, shape, particle size distribution, and hardness, the eight processes are still possible. Therefore, a sheet can be produced by randomly bonding the flat surfaces of a collection of soft magnetic flat powder made of multiple types of alloys, excluding reduced iron powder, with a collection of nickel nanoparticles. This sheet provides the following effects similar to those described in paragraph 21: First, in a collection of soft magnetic flat powder consisting of multiple alloys, 6-8 nickel nanoparticles are deposited in layers in the gaps between the flat surfaces of the flat powder, forming a very thin bonding layer with a thickness of 60-80 nm, randomly bonding the flat surfaces together. Because the size of the nickel nanoparticles is more than two orders of magnitude smaller than the area of ​​the flat powder, the properties of the flat powder of multiple alloys dominate in a sheet consisting of multiple alloys. Second, because the sheet is formed on the bottom of the container in the shape of the bottom, there are no restrictions on the area and shape of the sheet. Furthermore, even if the soft magnetic flat powder is made of multiple types of alloys (excluding reduced iron powder) and has different flatness, shape, particle size distribution, and hardness, eight processes for forming the sheet are possible. Therefore, it is possible to produce a sheet in which the flat surfaces of flat powder made of multiple types of alloys (excluding reduced iron powder) are bonded together with a cluster of nickel nanoparticles. Therefore, this sheet manufacturing method can be used to produce sheets with versatility for soft magnetic flat powders (excluding flat reduced iron powder). Third, a sheet made by stacking flat surfaces of soft magnetic flake powder made from multiple alloys with high relative magnetic permeability has a high magnetic shielding effect. Furthermore, if the thickness of the sheet is close to the skin depth of the flake powder, a sheet with a large surface area can be formed using a small amount of flake powder, and all of the flake powder will participate in magnetic shielding, increasing the magnetic shielding effect. Fourth, if soft magnetic flake powders made of multiple alloys have different frequency characteristics of the imaginary part of their complex permeabilities, and the frequency characteristics of the imaginary part of each complex permeability complement each other in different frequency ranges, a sheet made from a collection of soft magnetic flake powders made of multiple alloys will absorb electromagnetic noise over a wide frequency range, which was previously difficult to achieve. Furthermore, if the thickness of the sheet is made close to the skin depth of the flat powders of multiple alloys, a wide-area sheet can be formed using a small amount of flat powder, and all of the flat powder will participate in absorbing electromagnetic noise, improving the electromagnetic noise absorption effect. As described above, the sheet made by this manufacturing method, which is made from a collection of soft magnetic flat powders of multiple types of alloys, has the flat surfaces of the soft magnetic flat powders of multiple types of alloys randomly bonded together with a collection of nickel nanoparticles, and therefore has the functional effects of soft magnetic flat powders of multiple types of alloys that are not found in collections of conventional soft magnetic flat powders.

[0024] The method for producing a sheet made of a collection of flat powder described in paragraph 18 is a method for producing a sheet made of a collection of flake powder of a metal or alloy, and the method for producing a sheet made of a collection of flake powder of the metal or alloy is as follows: The flat powder described in paragraph 18 is silver, copper, brass, nickel, or aluminum. 1 type and the organometallic compound described in paragraph 18 is either copper octylate, aluminum octylate, or nickel octylate. 1 type and any of the above metal octylate compounds. 1 typea metal or alloy flake powder made of the material described above is used as the flat powder described in paragraph 18, and any of the above metal octylate compounds is used as the organometallic compound described in paragraph 18, according to a method for producing a sheet consisting of an aggregate of the flat powder described in paragraph 18, 1 type The flat surfaces of the metal or alloy flake powder made of the material are bonded together via a group of nanoparticles made of copper, aluminum, or nickel. Either one of the following Metal or If Manufacturing a sheet made of an aggregate of gold flake powder, and a method for manufacturing a sheet made of an aggregate of metal or alloy flake powder 。

[0025] First, a method for producing the flake powder made of metal or alloy used in the present invention will be described. Flake powder made of silver, copper, brass, or nickel, excluding aluminum, is produced by using a stamp mill to pound metal or alloy powder made of silver, copper, brass, or nickel with a number of metal pestles, stretching the powder into thin flakes, and flattening the powder to produce thin flake powder. ofBrass flake powder is sometimes called nickel flake powder. When this metal or alloy flake powder is pounded with multiple metal pestles, undulations form on the surface, resulting in poor flatness. On the other hand, aluminum, due to its high activity, is produced by atomizing fine particles, which are then flattened in a wet ball mill to produce scaly flake powder. This aluminum flake powder has a surface roughness due to the flattening process using a wet ball mill. These metal or alloy flake powders have a high aspect ratio, which is the ratio of thickness to the long axis. Therefore, by overlapping the flat surfaces, a sheet of a certain area can be formed from a small amount of flake powder. Furthermore, because the flake powder surface is smooth, the coefficient of friction is low, at 0.20-0.25. For this reason, metal or alloy flake powder has a lubricating surface, and combines electrical and thermal conductivity based on the material with the inherent color and luster of the metal or alloy. Among soft metals, tin has a melting point of 232°C, which is lower than the thermal decomposition temperature of metal octylate compounds, and it also becomes brittle at low temperatures around -40°C. Similarly, zinc also becomes brittle at low temperatures. For this reason, flake powders made of tin and zinc were excluded from the raw materials used to create sheets made from a collection of flake powders. Next, the material of the nanoparticles that bond the flat surfaces of the metal or alloy flake powder together will be described. If the nanoparticle material has excellent electrical and thermal conductivity, a sheet made of a collection of flake powder bonded together with a collection of metal nanoparticles will have a wide area and excellent electrical and thermal conductivity, which cannot be achieved with flat powder. Furthermore, if the nanoparticles are made of a transparent material, a sheet made of a collection of flake powder bonded together with a collection of transparent nanoparticles will have the inherent color and luster of the metal or alloy. Meanwhile, the electrical conductivity of metals is best in the following order: silver, copper, gold, aluminum, calcium, and magnesium. Furthermore, the thermal conductivity of metals is best in the following order: silver, copper, gold, aluminum, magnesium, and zinc. Furthermore, it is desirable that the metal octylate compound, which is the raw material for the nanoparticles, is relatively inexpensive. Therefore, when producing a sheet with excellent electrical and thermal conductivity, it is appropriate to bond the flat surfaces of the flake powder together with nanoparticles made of copper or aluminum. Meanwhile, when producing a sheet with the inherent color and luster of a metal or alloy, it is appropriate to bond the flat surfaces of the flake powder together with a collection of transparent nanoparticles. Since the collection of nanoparticles made of aluminum or nickel is transparent, the collection of flake powder bonded with the collection of nanoparticles made of aluminum or nickel becomes a sheet with the inherent color and luster of the flake powder. Here, we will explain transparent nanoparticles. A transparent material must have two characteristics: a refractive index of 0.4 to 2.4 in the visible light wavelength range, and a particle size at least one order of magnitude smaller than the wavelength of visible light. Specifically, when flat surfaces of flake powder are bonded together using a material with a refractive index of 0.4 to 2.4, the refractive index is close to the refractive index of air (1). Therefore, due to the surface reflectance and total light transmittance, more than 70% of visible light is incident on the flat surfaces of the flake powder. Surface reflectance and total light transmittance are explained in paragraph 27. Furthermore, when the size of the particles is at least one order of magnitude smaller than the wavelength of visible light, the collection of particles hardly scatters visible light, allowing it to transmit with high transparency. As a result, when a collection of nanoparticles with a refractive index of 0.4 to 2.4 and a size nearly two orders of magnitude smaller than the wavelength of visible light is formed on the surface of flake powder, visible light can pass through the collection of nanoparticles. Furthermore, when flat surfaces are joined together via a collection of nanoparticles, visible light passes through the gaps between the flat surfaces. The scattering of light in a collection of fine particles is explained in paragraph 27. Transparent materials that combine these two characteristics include nanoparticles made of nickel or aluminum, which have a refractive index of 0.4 or more and 2.4 or less in the visible light wavelength range (380-750 nm). The refractive index of nickel is 1.61 at 380 nm, increasing with wavelength to 1.75 at 539 nm, 2.21 at 709 nm, 2.28 at 729 nm, and 2.34 at 750 nm. Light is reflected by the surface of the nickel nanoparticle clusters covering the surface of the flake powder clusters and the surface of the bonding layer made of nickel nanoparticle clusters joining the flat surfaces of the flake powder due to the difference in refractive index between air and nickel. The light transmittance is 89% at 380 nm, 86% at 539 nm, 74% at 709 nm, 72% at 729 nm, and 70% at 750 nm. Therefore, a portion of the red visible light component is reflected by the surface of the nickel nanoparticle clusters. Furthermore, the size of nickel nanoparticles is nearly two orders of magnitude smaller than the wavelength of visible light. Therefore, light that enters the nickel nanoparticle clusters passes through them with almost no scattering. In contrast, the refractive index of aluminum reaches a maximum of 2.80 at 800 nm and rapidly decreases as the wavelength shortens, reaching 2.40 at 750 nm, 1.91 at 708 nm, and 0.45 at 380 nm, approaching the refractive index of air at 1 at 560 nm. Light is therefore reflected from the surface of aluminum nanoparticles due to the difference in refractive index between air and aluminum. The light transmittance is 69% at 750 nm, 81% at 708 nm, 100% at 560 nm, 89% at 450 nm, and 73% at 380 nm. This results in a portion of red and violet visible light being reflected from the surface of aluminum nanoparticles. Furthermore, the size of aluminum nanoparticles is nearly two orders of magnitude smaller than the wavelength of visible light. Therefore, light that enters aluminum nanoparticles passes through the nanoparticles with almost no scattering. As explained above, in a cluster of aluminum nanoparticles, some of the light rays that make up visible light are reflected by the surface of the cluster of aluminum nanoparticles, emitting a color corresponding to this light, but the cluster of aluminum nanoparticles is transparent. Also, in a cluster of nickel nanoparticles, the cluster of nickel nanoparticles is nearly colorless and also transparent. As explained above, the cluster of nanoparticles made of aluminum or nickel maintains its transparency and bonds the flat surfaces of the flake powder together. Therefore, the color and luster reflected by the flake powder are not lost. Next, we will explain the phenomenon that occurs when flat surfaces of flake powder made of metal or alloy are bonded together with a collection of nanoparticles. The Mohs hardness of the silver, copper, brass, nickel, or aluminum that make up the flake powder is 2.7 for silver, 2.9 for aluminum, 3.0 for copper, 3-4 for brass, and 3.5 for nickel. The Young's modulus is 69 GPa for aluminum, 82.7 GPa for silver, 130 GPa for copper, 103 GPa or 110 GPa for brass, and 204 GPa for nickel. Therefore, the metals or alloys that make up the flake powder all have low Mohs hardness. On the other hand, because the nanoparticles are approximately 10 nm in size, the thickness of the thinnest flake powder is 20 times the size of the nanoparticle, while the surface area of ​​the flat powder with the smallest surface area is 1,000 times the size of the nanoparticle. The contact area of ​​the nanoparticles with the flat surfaces of such flake powder is extremely small. Furthermore, the contact area between nanoparticles is also extremely small. On the other hand, as mentioned above, metals or alloys other than nickel have a small Young's modulus and are excellent in ductility and malleability. Therefore, when flat surfaces of flake powder made of a metal or alloy other than nickel are joined together with a collection of nanoparticles made of copper or aluminum, the copper or aluminum nanoparticles come into contact with the flat surfaces, and localized areas of contact on the flat surfaces undergo elastic deformation. At this time, frictional heat is generated at the localized areas of contact. On the other hand, since the nanoparticles are also made of copper or aluminum, which has a small Young's modulus, localized areas of contact on the nanoparticles undergo elastic deformation. At this time, frictional heat is generated at the localized areas of contact. Due to the frictional heat between the two, the flat surfaces of the flake powder made of the metal or alloy are joined together with the collection of nanoparticles made of copper or aluminum. Furthermore, localized areas of contact between the copper or aluminum nanoparticles undergo elastic deformation, and frictional heat is generated at the localized areas of contact. This causes the copper or aluminum nanoparticles to bond together through frictional heat. Meanwhile, when the copper or aluminum nanoparticles come into contact with the flat surfaces of the nickel flake powder, localized areas of the nanoparticles at the contact point undergo elastic deformation. At this time, frictional heat is generated at the localized areas of the contact point.On the other hand, because nickel flake powder has a large Young's modulus, localized areas of contact on the flat surfaces do not elastically deform, but frictional heat is generated. The frictional heat between the two causes the flat surfaces of the nickel flake powder to bond together with the clusters of copper or aluminum nanoparticles. Furthermore, localized areas of contact between the copper or aluminum nanoparticles elastically deform, generating frictional heat at the localized areas of contact. As a result, the copper or aluminum nanoparticles bond together with frictional heat. In contrast, when nickel nanoparticles come into contact with the flat surfaces of metal or alloy flake powder, localized areas of contact on the flat surfaces undergo elastic deformation first. At this time, frictional heat is generated at the localized areas of contact. On the other hand, because nickel nanoparticles have a large Young's modulus, localized areas of contact on the nanoparticles do not undergo elastic deformation, but frictional heat is generated. Therefore, the frictional heat between the two causes the flat surfaces of the metal or alloy flake powder to bond together with the collection of nickel nanoparticles. In addition, frictional heat is generated at localized areas of contact between nickel nanoparticles. As a result, the nickel nanoparticles are bonded together by frictional heat. As a result, the flat surfaces of the metal or alloy flake powder are bonded together by the aggregation of nanoparticles made of copper, aluminum, or nickel. The nanoparticles are also bonded together by frictional heat. The heat resistance temperature of metal or alloy flake powder is determined by its softening point, with aluminum having the lowest softening point of 350°C. Furthermore, metals or alloys made of silver, copper, brass, nickel, or aluminum are not brittle at low temperatures, making them suitable for use at extremely low temperatures. Therefore, sheets made from an assembly of flake powder, with the flat surfaces of the flake powder joined together, can be used in harsh environments where oil lubrication is not possible, such as high temperatures, extremely low temperatures, ultra-vacuum, and ultra-high pressure. Furthermore, they have a high load-bearing capacity of over 600 MPa. Therefore, when the assembly of flake powder is compressed, the flat surfaces of the flake powder can withstand the compressive stress. As mentioned above, the softening point of aluminum is low at 350°C. On the other hand, when flat surfaces of aluminum flake powder are joined together with a collection of copper, aluminum, or nickel nanoparticles, the contact area of ​​the copper, aluminum, or nickel nanoparticles with the flat surfaces is extremely small. Therefore, even when flat surfaces of aluminum flake powder are joined together with a collection of aluminum nanoparticles, the contact area between the aluminum flat surfaces and the aluminum nanoparticles does not soften. Metal or alloy flake powders have smooth surfaces, but they are not flat and have inherent undulations. Meanwhile, the size of copper, aluminum, or nickel nanoparticles is nearly two orders of magnitude smaller than the irregularities of the flat surfaces. Therefore, regardless of the flatness of the flat surfaces and the irregularities of the surfaces, the entire surfaces of the flat surfaces are bonded together via clusters of copper, aluminum, or nickel nanoparticles. Furthermore, when aluminum flake powder is flattened using a wet ball mill, irregularities form on the surface. However, the size of copper, aluminum, or nickel nanoparticles is more than two orders of magnitude smaller than the irregularities of the flat surfaces. Therefore, regardless of the irregularities of the flat surfaces of aluminum flake powder, the entire surfaces of the flat surfaces are bonded together via clusters of copper, aluminum, or nickel nanoparticles. The thickness of metal or alloy flake powder varies from 0.2 to 1 μm depending on the material, but within the grade of the product used, the thickness deviation is within 0.1 μm. Also, even if the material of the flake powder is the same, the particle size varies depending on the product because the flattening conditions differ for each product. On the other hand, the density of metal or alloy varies greatly depending on the material. Aluminum has a density of 2.7 g / cm 3 And silver is 10.5g / cm 3 And copper is 9.0g / cm 3 And brass is 8.7g / cm 3 And nickel is 8.9g / cm 3 However, even if the flake powder has the highest density and the flat powder is relatively large, that is, the density is 10.5 g / cm 3Even if the particle size of silver flake powder is 100 μm and the thickness is 0.5 μm, the weight of the flake powder is only 4.5 × 10 -8 g. Next, we will explain metal octylate compounds that precipitate metals upon thermal decomposition. A metal carboxylate compound that combines the first characteristic—that the oxygen ions constituting the carboxyl group of the carboxylic acid are covalently bonded to the metal ion—and the second characteristic—that the carboxylic acid is composed of saturated fatty acids—has the largest metal ion, and the distance between the oxygen ions constituting the carboxyl group and the metal ion is longer than the distance between other ions. When a metal carboxylate compound with these molecular structural characteristics is heat-treated in air, the bond between the oxygen ions constituting the carboxyl group and the metal ion breaks first when the temperature exceeds the boiling point of the carboxylic acid, resulting in separation of the carboxylic acid and the metal. When the carboxylic acid is composed of saturated fatty acids, there is no unsaturated structure in which carbon atoms are in excess of hydrogen atoms. Therefore, depending on the molecular weight and number of the carboxylic acid, the carboxylic acid absorbs the heat of vaporization and vaporizes, and the metal precipitates upon completion of vaporization. Furthermore, metal carboxylate compounds disperse in methanol at concentrations close to 10% by weight but are insoluble in methanol. Therefore, metal carboxylate compounds that combine these two characteristics can be used as the organometallic compounds described in paragraph 17. Examples of such metal carboxylate compounds include metal octylate compounds, metal laurate compounds, and metal stearate compounds. The boiling points of octylate, laurate, and stearic acid are 228°C, 296°C, and 361°C, respectively. Therefore, these metal carboxylate compounds undergo complete thermal decomposition in an air atmosphere at 290-430°C. Among metal carboxylate compounds, metal octylate compounds have the lowest thermal decomposition temperature, making them the most desirable metal carboxylate compounds. Furthermore, when metal octylate compounds are thermally decomposed in a nitrogen atmosphere, the thermal decomposition reaction proceeds more slowly, resulting in a thermal decomposition temperature of 340°C. Furthermore, metal carboxylate compounds are inexpensive industrial chemicals that can be easily synthesized. That is, when carboxylic acids, the most commonly used organic acids, are reacted with strong alkalis, alkali metal carboxylate compounds are produced, and when alkali metal carboxylate compounds are reacted with inorganic metal compounds, metal carboxylate compounds composed of various metals are synthesized. Therefore, metal carboxylate compounds are the least expensive of all organometallic compounds. Next, we will explain each of the phenomena that occur when producing a sheet using flake powder made of a metal or alloy as the flat powder described in paragraph 18, copper octylate, aluminum octylate, or nickel octylate as the organometallic compound described in paragraph 17, and the method for producing a sheet consisting of a collection of flat powder described in paragraph 18, and the effects and actions that each of these phenomena brings about. First, the substance that bonds the flat surfaces of the flake powder is a cluster of nanoparticles of copper, aluminum, or nickel, and then the raw material for the nanoparticles, a metal octylate compound, is dispersed in methanol to create a liquid phase. Because this liquid has low viscosity and density, by continuously carrying out the second and third processes, it becomes possible to interpose the methanol dispersion of the metal octylate compound in the gaps between the flat surfaces of the separated flake powder. Second, a homogenizer is operated within the container, repeatedly generating shock waves. Because the methanol dispersion of the metal octylate compound has low viscosity and density, the shock waves consume only a small proportion of the energy required to excite the methanol dispersion of the metal octylate compound, and much of the shock energy is efficiently and repeatedly transmitted to the flake powder. Furthermore, as mentioned above, the weight of each flake powder is extremely light. Therefore, even if the flake powder has complex overlapping flat surfaces, when shock waves are applied to the flake powder, it is reliably separated into individual flake powders. Regardless of the material, shape, or particle size distribution of the flake powder, the methanol dispersion of the metal octylate compound comes into contact with the surface of all the flake powder. Furthermore, the surfaces of all flake powders are hydrophobic and do not react with the methanol dispersion of the metal octylate compound, allowing the methanol dispersion of the metal octylate compound to come into contact with the surface of the flake powder. Third, the container has three directions: left and right, front and back, and top and bottom. Impact force Repeatedly add Impact force At this time, since the methanol dispersion of the metal octylate compound has low viscosity and density and each flake powder is extremely light, the methanol dispersion of the metal octylate compound is mixed with the flake powder. impact It moves repeatedly in the direction of acceleration. When this phenomenon is repeated in three directions (left and right, front and back, and up and down), the soft magnetic flake powder rearranges with the flat surfaces facing up, causing the flat surfaces to overlap, a phenomenon that progresses in the methanol dispersion of the metal octylate compound. As a result, the flake powder spreads over the entire bottom surface of the container, and a collection of flat powder with overlapping flat surfaces forms the shape of the bottom surface of the container through the methanol dispersion of the metal octylate compound. Fourth, because the individual flake powders are stacked together with their flat surfaces interposed in a methanol dispersion of a metal octylate compound, the larger the aspect ratio of the flake powder, the less flake powder is required. Therefore, even if the flake powder is expensive, the amount of flake powder required is small, making it possible to inexpensively produce sheets made of a collection of flake powder. Fifth, the flat surfaces of the flake powder are stacked together via a methanol dispersion of the metal octylate compound, and methanol is evaporated from the resulting cluster of flake powder, precipitating clusters of fine crystals of the metal octylate compound in the gaps between the flat surfaces and on the surface of the cluster of flake powder. The entire surface of the cluster of flake powder is then evenly compressed. This crushes the fine crystals to about one-fifth their original size, and the crushed crystal clusters overlap and accumulate at high density in the gaps between the flat surfaces and on the surface of the cluster of flake powder. These crushed fine crystals of the metal octylate compound, each about 20 nm in size, become the raw material for clusters of copper, aluminum, or nickel nanoparticles, each about 10 nm in size, that connect the flat surfaces of the flake powder. Sixth, the entire surface of the flake powder mass is heated while being uniformly compressed, causing the crushed fine crystals of the octylate metal compound to thermally decompose. During this process, clusters of copper, aluminum, or nickel nanoparticles approximately 10 nm in size are deposited simultaneously in high density in the gaps between the flat surfaces of the flake powder and on the surface of the flake powder mass. Furthermore, the entire surface of the flake powder mass is uniformly compressed, and the clusters of copper, aluminum, or nickel nanoparticles deposited at high density are bonded to the flat surfaces by frictional heat, and the copper, aluminum, or nickel nanoparticles are also bonded to each other by frictional heat. In other words, because clusters of copper, aluminum, or nickel nanoparticles are precipitated overlapping each other at high density, the compressed nanoparticles have difficulty moving within the cluster of nanoparticles, and frictional heat is generated at the contact points of the nanoparticles with the flat surface and at the contact points between the nanoparticles, and the bonding force generated by the frictional heat bonds the copper, aluminum, or nickel nanoparticles to the flat surface, and also bonds the copper, aluminum, or nickel nanoparticles with each other due to the bonding force generated by the frictional heat. Seventh, flake powders made of silver, copper, brass, nickel, or aluminum can be used as flat powders when producing sheets made of aggregated flake powders. Specifically, the thermal decomposition temperature of metal octylate compounds is 290°C in air. Meanwhile, the softening points of flat powders made of silver, copper, brass, nickel, or aluminum are all higher than 290°C, and none of these flake powders exhibit low-temperature brittleness, making them suitable for use at cryogenic temperatures. Therefore, sheets made of aggregated flake powders with their flat surfaces bonded together can be used in harsh environments, such as high temperatures, cryogenic temperatures, vacuum, and high pressure. The thermal decomposition temperature of metal octylate compounds in a nitrogen atmosphere is 340°C, 50°C higher than in air. Meanwhile, aluminum has the lowest softening point of 350°C among flake powders made of metals or alloys. Therefore, aluminum does not soften even when metal octylate compounds are thermally decomposed in a nitrogen atmosphere. Eighth, the flat surfaces of the flake powder are bonded together with a collection of copper, aluminum, or nickel nanoparticles. Both copper and aluminum are metals or alloys that have excellent electrical and thermal conductivity. Therefore, the copper or aluminum nanoparticles do not impair the electrical and thermal conductivity of the flake powder made of a metal or alloy in a sheet in which the flat surfaces of the flake powder are bonded together. Furthermore, the nickel or aluminum nanoparticles are transparent. Therefore, the nickel or aluminum nanoparticles do not lose the color and luster inherent to the flake powder made of a metal or alloy in a sheet in which the flat surfaces of the flake powder are bonded together. Ninth, metal octylate compounds are general-purpose industrial chemicals. Furthermore, because the flat surfaces of the flake powder are bonded together, only a small amount of flake powder is required. Furthermore, all eight processes for bonding the flat surfaces together with clusters of copper, aluminum, or nickel nanoparticles are simple. Therefore, sheets made of clusters of flake powder can be produced using inexpensive materials at low cost. The sheet made of a collection of flake powder produced by the eight processes described above provides the following effects. First, in a cluster of flake powder made of metal or alloy, six to eight copper, aluminum, or nickel nanoparticles approximately 10 nm in size are stacked on top of each other to bond the flat surfaces of the flake powder. Because the size of the nanoparticles is more than two orders of magnitude smaller than the particle size of the flake powder, the properties of the flake powder dominate the sheet. Furthermore, both copper and aluminum are metals with excellent electrical and thermal conductivity among metals and alloys. Therefore, the bonding layer formed by the nanoparticle clusters does not impair the electrical and thermal conductivity of the metal or alloy flake powder in a sheet made of the flake powder cluster. Furthermore, nickel or aluminum nanoparticles have excellent transparency. Therefore, the bonding layer formed by the nanoparticle clusters does not lose the inherent color and luster of the metal or alloy flake powder in a sheet made of the flake powder cluster. Second, because the sheet is formed on the bottom of the container in the shape of the bottom, there are no restrictions on the area and shape of the sheet. Furthermore, the eight processes described above are possible for all flake powders made of metals or alloys, regardless of differences in the flatness, shape, or particle size distribution of the flake powder. Therefore, for all flake powders made of metals or alloys, a sheet can be produced in which the flat surfaces of the flake powders are bonded together with a collection of copper, aluminum, or nickel nanoparticles. Therefore, this sheet manufacturing method can be used to form a versatile sheet made of a collection of flake powders for any flake powder made of metals or alloys. As explained above, the sheet made from the aggregate of flake powder produced by this production method can be formed into a sheet with a large area using a small amount of flake powder. This sheet has excellent electrical and thermal conductivity, and retains the color and gloss unique to the flake powder. It can also be used as an antistatic sheet, an electromagnetic wave shielding sheet, or a sheet with an excellent surface lubricity.

[0026] Let's explain surface reflectance and total light transmittance. When light enters a substrate, surface reflection occurs depending on the difference in refractive index between air and the substrate. Therefore, even transparent glass experiences loss due to surface reflection, and total light transmittance does not reach 100%. Incidentally, a 2mm-thick float glass has a total light transmittance of approximately 90% in the visible light wavelength range. The surface reflectance R of light incident perpendicularly on the substrate is calculated using Equation 2, which is made up of the refractive index n of the substrate and the refractive index m of air. Total light transmittance T is calculated using Equation 3, which is also made up of the surface reflectance R. Therefore, if the refractive index of the metal is 0.4, the total light transmittance incident on the conductive layer will be 67%. If the refractive index of the metal is 2.4, the total light transmittance incident on the conductive layer will be 69%, meaning that more than 70% of visible light will enter the conductive layer. (Number 2) R = (n-m) 2 / (n+m) 2 (Number 3) T=(1-R) 2

[0027] Next, we will explain light scattering. When visible light is irradiated onto a collection of particles, the Rayleigh scattering equation shown in Equation 4 can be applied to the scattering of light. In Equation 4, S is the scattering coefficient, which indicates the scattering ratio, where λ is the wavelength of visible light, D is the particle diameter, m is the refractive index of the particle, and π is the circular constant. Therefore, the magnitude of the scattering coefficient S depends on the fourth power of the ratio D / λ of the particle diameter D to the wavelength λ of visible light, and also on the square of the particle diameter D and the refractive index m. Because the size D of the nanoparticles is nearly two orders of magnitude smaller than the wavelength λ of visible light, the ratio D / λ is small, and the particle diameter D is also sufficiently small. Furthermore, the refractive index m of the metal is between 0.4 and 2.4. Therefore, the scattering coefficient S is extremely small, and the conductive layer exhibits high transparency. (Number 4) S=4 / 3·π 5 / λ 4 D 6 {(m 2 -1) / (m 2 +1)} 2

[0028] The method for producing a sheet made of an aggregate of flat powder described in paragraph 18 is a method for producing a sheet made of an aggregate of insulating flat powder made of metal oxides or inorganic compounds, and the method for producing a sheet made of an aggregate of insulating flat powder made of metal oxides or inorganic compounds is as follows: The flat powder described in paragraph 18 is glass, alumina or hematite 1 type The insulating flat powder is made of a metal oxide or an inorganic compound, and the organometallic compound described in paragraph 18 is made of the metal oxide or The aforementioned A complex made of a metal carboxylate compound that precipitates an insulating metal oxide by thermal decomposition, the insulating metal oxide having a hardness lower than that of the insulating flat powder made of an inorganic compound, 1 type The method for producing a sheet consisting of an assembly of flat powders described in paragraph 18 is to use an insulating flat powder consisting of a metal oxide or an inorganic compound made of the material described above as the flat powder described in paragraph 18, and to use a complex consisting of the carboxylic acid metal compound as the organometallic compound described in paragraph 18, and to produce a sheet consisting of the assembly of flat powders described in paragraph 18, The aforementioned The flat surfaces of insulating flat powder made of inorganic compounds are Applicable A method for producing a sheet consisting of an assembly of insulating flat powder made of a metal oxide or an inorganic compound, the assembly being bonded via an assembly of nanoparticles made of an insulating metal oxide having a hardness lower than that of the insulating flat powder, and a method for producing a sheet consisting of an assembly of insulating flat powder made of a metal oxide or an inorganic compound. 。

[0029] First, the insulating flat powder made of a metal oxide or an inorganic compound used in the present invention will be described. The electrical resistivity of flat powders made of glass and alumina is 10 14 It has a high insulating property of over Ωcm. Therefore, if the flat surfaces of flat powders made of these metal oxides or inorganic compounds are joined together with a collection of nanoparticles made of insulating metal oxides, an insulating sheet with extremely high insulating resistance is formed. The main components of glass are silicon dioxide and boron oxide, and since silicon and boron are semi-metallic elements, silicon dioxide and boron oxide are inorganic compounds. Other components include metal oxides such as alumina, lead oxide, sodium oxide, potassium oxide, and calcium oxide. For this reason, glass is made up of a mixture of metal oxides and inorganic compounds. Of the glass flake powders, only soda-lime glass has a density of 10 12 The flat powder of hematite (a substance consisting of the alpha phase of ferric oxide Fe2O3) has an electrical resistivity of 10 8 However, if the thickness of the hematite flake powder is submicron and the cross-sectional area of ​​the hematite flake powder is 0.3 μm × 10 μm, the electrical resistance per unit length of the flake powder is 3.3 × 10 16Ω / cm. The electrical resistance of a sheet in which the flat surfaces of this hematite powder are bonded together by a collection of nanoparticles made of insulating metal oxide forms an insulating sheet with extremely high insulation resistance. That is, the collection of a very large number of nanoparticles made of insulating metal oxide that bond the flat surfaces of the hematite powder together forms an electrical resistance in which the collection of nanoparticles made of insulating metal oxide is connected in series. Furthermore, flat powder in which the flat surfaces of hematite are bonded together via this collection of nanoparticles has an electrical resistance in which the electrical resistance of the flat powder and the electrical resistance of the collection of nanoparticles are connected in parallel. When such flat powder connected via a collection of nanoparticles forms a sheet with a huge number of flat powders, the flat powders are electrically bonded by forming parallel and series connections, so that a sheet made of a collection of flat powder in which flat powders of hemite are bonded together via a collection of nanoparticles made of insulating metal oxide becomes an insulating sheet with extremely high insulation resistance. Similarly, a sheet made by bonding flat powders made of glass or alumina together via a collection of nanoparticles made of insulating metal oxides also becomes an insulating sheet with extremely high insulation resistance.Hematite flat powder is a red pigment called red iron oxide, and is a general-purpose flat powder. As explained above, flat powder made of glass, alumina or hematite is an excellent raw material for an insulating sheet having extremely high insulation resistance. Here, the characteristics of the insulating flat powder made of glass, alumina, and hematite will be described. Glass flake powder with an average thickness of 2-5 μm and particle size of 10-4000 μm is commercially available. Fine flake powder with an average thickness of 0.4-1.0 μm is also commercially available. The Mohs hardness is 5-6. The glass material is C glass or E glass. Flat powder made of alumina is produced by heating flaky flat powder of boehmite, an alumina hydrate, to over 500°C. Three types of flat powder with an aspect ratio of 20-40 and average particle sizes of 2 μm, 5 μm, and 9 μm are commercially available. The specific gravity is 3.98 g / cm 3 The Mohs hardness is high at 9. The flat powder made of hematite has a specific gravity of 5.2 g / cm3 Flat powders with an average particle size of 10-20 μm and an average particle thickness of 0.1-0.4 μm are commercially available. The Mohs hardness is 5.5. Even E-glass flat powder, which has an extremely large particle size of 4000 μm and a relatively thick thickness of 2 μm, weighs only 1.7 x 10 -6 g. On the other hand, when excessive compressive stress is applied to the flat surfaces of insulating flat powder, the flat powder does not undergo plastic deformation and undergoes brittle fracture. For this reason, when joining flat surfaces with a collection of insulating nanoparticles made of metal oxide, the thinner the flat powder, the more likely it is to undergo brittle fracture. Therefore, the nanoparticles are made of a metal oxide whose hardness is lower than that of the flat powder, so that excessive compressive stress is not applied to the flat surfaces when the collection of nanoparticles comes into contact with the flat surfaces. Here, the hardness of metal oxides will be explained. Metal oxide particles have increasing hardness in the following order: aluminum oxide (Al2O3), silicon oxide (SiO2), tin oxide (SnO2), chromium oxide (Cr2O3), magnesium oxide (MgO), and titanium oxide (TiO2). Furthermore, manganese oxide (MnO2), copper oxide (CuO), nickel oxide (NiO), and zinc oxide (ZnO). Therefore, the nanoparticles bonding the glass flake powders together may be composed of an insulating metal oxide that is less hard than tin oxide and has a Mohs hardness of less than 5. Furthermore, the nanoparticles bonding the alumina flake powders together may be composed of an insulating metal oxide that is less hard than aluminum oxide and has a Mohs hardness of less than 9. Furthermore, the nanoparticles bonding the hematite flake powders together may be composed of an insulating metal oxide that is less hard than chromium oxide and has a Mohs hardness of less than 5.5. Next, we describe a complex of a metal carboxylate compound that precipitates a metal oxide upon thermal decomposition. The complex precipitates a metal oxide when heat-treated in an air atmosphere at temperatures between 180 and 330°C. Among flat powders made of glass, alumina, or hematite, glass has the lowest softening point, at 355°C. Therefore, the thermal decomposition temperature of the complex of a metal carboxylate compound is lower than that of flat powders made of glass, alumina, or hematite. Furthermore, the complex of a metal carboxylate compound disperses in methanol but does not dissolve in it. Therefore, the complex of a metal carboxylate compound can be used as the organometallic compound described in paragraph 18. That is, the carboxylate anion of carboxylic acid (R-COO - A complex consisting of a carboxylate metal compound in which a ligand approaches and coordinates with a metal ion is formed by bonding a carboxylate anion (R-COO) to the metal ion, which is the largest ion. - ) approach each other and form a coordinate bond, shortening the distance between them. This allows the carboxylate anion (R-COO - ) is at the longest distance from the ion covalently bonded to the opposite side of the metal ion. When the boiling point of the carboxylic acid is exceeded, the carboxylate anion (R-COO - The bond between the metal ion and the covalent ion on the other side of the metal ion is first broken, and the carboxylic acid decomposes into a metal oxide, which is a compound of the metal ion and oxygen ion, and a carboxylic acid. If the temperature is further increased, the carboxylic acid absorbs the heat of vaporization and vaporizes. The vaporization of the carboxylic acid progresses depending on the molecular weight of the carboxylic acid and the number of carboxylic acids in the coordinate bond. Once vaporization is complete, the metal oxide precipitates, completing the thermal decomposition. Metal carboxylate compounds with these molecular structural characteristics include, in order of decreasing thermal decomposition temperature, metal acetate compounds, metal caprylate compounds, metal benzoate compounds, and metal naphthenate compounds. Complexes consisting of these metal carboxylate compounds thermally decompose in an air atmosphere at 180-330°C depending on the boiling point of the carboxylic acid. In other words, the boiling point of acetic acid is 118°C, that of caprylic acid is 237°C, and that of benzoic acid is 249°C. On the other hand, naphthenic acid is a mixture of saturated fatty acids with a five-membered ring, and has the general formula C n H 2n-1 It is represented by COOH and its main component is CH with a boiling point of 268°C and a molecular weight of 170. 17 It consists of COOH. Therefore, the thermal decomposition temperature of metal naphthenate compounds is high at 330°C among complexes consisting of metal carboxylate compounds. Therefore, metal acetate compounds, metal caprylate compounds, metal benzoate compounds, or metal naphthenate compounds can be used as the organometallic compound described in paragraph 17. Furthermore, flat powders made of glass, alumina, or hematite are inorganic compounds made of metal oxides or semimetal oxides, so they do not oxidize even when heated to 330°C in an air atmosphere. On the other hand, among metal acetate compounds, there are metal acetate compounds that dissolve in methanol. There are also metal acetate compounds that precipitate amorphous metal oxides upon thermal decomposition. The composition of the amorphous metal oxides is not constant. These metal acetate compounds cannot be used as raw materials for metal oxide microparticles. Furthermore, among metal acetate compounds or metal caprylate compounds, there are metal acetate compounds or metal caprylate compounds that precipitate amorphous metal oxides upon thermal decomposition. These metal acetate compounds or metal caprylate compounds cannot be used as raw materials for metal oxide microparticles. Furthermore, among metal acetate compounds, metal caprylate compounds, and metal benzoate compounds, oxygen ions approach and coordinate with metal ions to form binuclear complex salts, but these metal acetate compounds, metal caprylate compounds, and metal benzoate compounds are unstable substances during thermal decomposition and are difficult to handle during thermal decomposition. Among these metal carboxylate compounds, metal naphthenate compounds are used as raw materials for insulating metal oxide microparticles. Therefore, depending on the substance to be precipitated by thermal decomposition, a complex made of a metal carboxylate compound is used as the raw material for the microcrystals. Furthermore, complexes of metal carboxylate compounds are inexpensive industrial chemicals that can be easily synthesized. That is, when a carboxylic acid is reacted with a strong alkali, an alkali metal carboxylate compound is produced. Then, when the alkali metal carboxylate compound is reacted with an inorganic metal compound, complexes of metal carboxylate compounds composed of various metals are synthesized. Furthermore, the raw material, carboxylic acid, is an inexpensive organic acid. Therefore, it is the cheapest organometallic compound among organometallic compounds. Here, we will explain the effects of a sheet produced according to the method for producing a sheet consisting of a collection of flat powders described in paragraph 18, using flat powders made of glass, alumina or hematite as the flat powder described in paragraph 18, and using nanoparticles of metal or metal oxide described in paragraph 18 made of insulating metal oxides with a hardness lower than that of the flat powder. First, the substance that bonds the flat surfaces of the flat powder is a collection of insulating metal oxide nanoparticles with a hardness lower than that of the flat powder, and then a complex made of a metal carboxylate compound, the raw material for the nanoparticles, is dispersed in methanol to create a liquid phase. Because this liquid has low viscosity and density, by continuously performing the second and third processes, it becomes possible to interpose the methanol dispersion of the complex made of a metal carboxylate compound in the gaps between the flat surfaces of the separated flat powder. Second, a homogenizer is operated in the container, and shock waves are repeatedly generated by the homogenizer. Meanwhile, because the methanol dispersion of the complex of the metal carboxylate compound has low viscosity and density, only a small proportion of the shock waves are consumed when exciting the methanol dispersion of the complex of the metal carboxylate compound, and much of the shock energy is efficiently and repeatedly transmitted to the collection of flat powder. Furthermore, as mentioned above, the weight of each flat powder is extremely light. Therefore, even flat powder with complex overlaps is reliably separated into individual flat powders when shock waves are applied to the flat powder. As a result, regardless of the material, shape, or particle size distribution of the flat powder, the methanol dispersion of the complex of the metal carboxylate compound comes into contact with the surface of all flat powders. Furthermore, the flat surfaces of all flat powders are hydrophobic and do not react with the methanol dispersion of the complex of the metal carboxylate compound, and the methanol dispersion of the complex of the metal carboxylate compound comes into contact with the flat surfaces. Third, the container has three directions: left and right, front and back, and top and bottom. Impact force Repeatedly add Impact force At this time, since the methanol dispersion of the complex made of the carboxylic acid metal compound has low viscosity and low density, and each flat powder is extremely light, the methanol dispersion of the complex made of the carboxylic acid metal compound is mixed with the flat powder. impactThe particles move repeatedly in the direction of acceleration. When this phenomenon is repeated in three directions (left and right, front and back, and up and down), the flat powder particles rearrange with the flat surfaces facing up and overlap in the methanol dispersion of the complex made of a carboxylic acid metal compound. As a result, the flat powder spreads over the entire bottom surface of the container, and a collection of flat powder particles with their flat surfaces overlapping each other through the methanol dispersion of the complex made of a carboxylic acid metal compound forms the shape of the bottom surface of the container. Fourth, the individual flake powders are separated and then stacked together with their flat surfaces in a methanol dispersion of a complex made of a metal carboxylate compound. This means that the larger the aspect ratio of the flake powder, the less flake powder is used. Therefore, even if the flake powder is expensive, only a small amount of flake powder is used, making it possible to inexpensively produce sheets made from a collection of flake powder. Fifth, methanol is evaporated from the flat powder aggregate, in which the flat surfaces of the flat powder are stacked together, via a methanol dispersion of a complex made of a metal carboxylate compound, to precipitate clusters of fine crystals of the complex made of a metal carboxylate compound in the gaps between the flat surfaces and on the surface of the aggregated flat powder. Furthermore, the entire surface of the aggregated flat powder is evenly compressed. This crushes the fine crystals to about one-fifth their original size, and the crushed crystal clusters overlap and accumulate at high density in the gaps between the flat surfaces and on the surface of the aggregated flat powder. These crushed fine crystals of the complex made of a metal carboxylate compound, which are approximately 20 nm in size, become the raw material for clusters of metal oxide nanoparticles, each approximately 10 nm in size, that connect the flat surfaces of the flat powder. Sixth, the entire surface of the flaky powder mass is heated while being uniformly compressed, causing the fine crystals of the complex composed of the crushed carboxylate metal compound to thermally decompose. During this process, clusters of metal oxide nanoparticles, each approximately 10 nm in size, are deposited simultaneously in high density in the gaps between the flat surfaces of the flaky powder and on the surface of the flaky powder mass. Furthermore, the entire surface of the flaky powder mass is uniformly compressed, and the clusters of metal oxide nanoparticles deposited at high density are bonded to the flat surfaces by frictional heat, and the metal oxide nanoparticles are also bonded to each other by frictional heat. In other words, because the clusters of metal oxide nanoparticles are deposited in a high density, overlapping each other, the compressed nanoparticles have difficulty moving within the cluster. Frictional heat is generated at the contact points of the nanoparticles with the flat surfaces and at the contact points between the nanoparticles. The metal oxide nanoparticles are bonded to the flat surfaces by the bonding force generated by the frictional heat, and the metal oxide nanoparticles are also bonded to each other by the bonding force generated by the frictional heat. Furthermore, since the nanoparticles are composed of insulating metal oxides with a hardness lower than that of the flat powder, when the nanoparticles come into contact with the flat surface, the contact points of the nanoparticles undergo very slight elastic deformation, and excessive compressive stress is not applied to the flat surface. As a result, the flat powder does not suffer brittle fracture. Furthermore, when nanoparticles come into contact with each other, the contact points of the nanoparticles undergo very slight elastic deformation, and excessive compressive stress is not applied to the contact points of the nanoparticles. Therefore, the nanoparticle clusters do not break. Furthermore, when the entire surface of the flat powder cluster is compressed, the nanoparticles are bonded to the flat surface by frictional heat, and after the nanoparticles have bonded to each other by frictional heat, if further compressive stress is applied to the flat powder cluster, a repulsive force is generated in the plate material to which the compressive stress is applied, because the nanoparticles have been miniaturized to the limiting size, and at this point, the compressive stress applied to the flat powder cluster is stopped. Seventh, flat powders made of glass, alumina, or hematite can be used as the flat powder when manufacturing sheets made of an aggregate of flat powders. Specifically, the thermal decomposition temperature of a complex made of a metal carboxylate compound is 330°C, the highest temperature in the air. Among flat powders made of glass, alumina, or hematite, the flat powder with the lowest softening point is glass flat powder, which has the lowest softening point of 355°C. Therefore, the thermal decomposition temperature of a complex made of a metal carboxylate compound is lower than the softening point of the flat powder. Therefore, sheets made of an aggregate of flat powders in which the flat surfaces of the flat powders are bonded together can be used in harsh environments such as high temperatures, cryogenic temperatures, vacuums, and high pressures. Among flat powders made of glass, alumina, or hematite, the flat powder with the lowest melting point is glass flake powder, which has a high melting point of 1200°C or higher. Furthermore, even if a sheet made of a collection of flat powder is heated above the softening point of the flat powder, as long as no stress that deforms the flat powder is applied to the sheet, the sheet made of a collection of flat powder will retain its original properties when returned to its original temperature. For this reason, sheets made of a collection of flat powder can be used at very high temperatures. Among metal oxide nanoparticles, the metal oxide with the lowest melting point is tin oxide, with a melting point of 1630°C. Eighth, the flat surfaces of the flat powder are bonded together with a collection of insulating metal oxide nanoparticles. The collection of a very large number of insulating metal oxide nanoparticles that bond the flat surfaces of the flat powder together forms an electrical resistance in which the collection of insulating metal oxide nanoparticles is connected in series. Furthermore, flat powder whose flat surfaces are bonded together through a collection of nanoparticles has an electrical resistance in which the electrical resistance of the flat powder and the electrical resistance of the collection of nanoparticles are connected in parallel. When a huge number of flat powders connected through such a collection of nanoparticles form a sheet, the flat powders are electrically bonded together by forming parallel and series connections, so the sheet made up of the collection of flat powder becomes an insulating sheet with extremely high insulation resistance. Ninth, complexes made from carboxylic acid metal compounds are general-purpose industrial chemicals. Furthermore, because the flat surfaces of the flat powder are bonded together, only a small amount of flat powder is required. Furthermore, all eight processes for bonding the flat surfaces together with a cluster of metal oxide nanoparticles are simple. Therefore, insulating sheets with high insulation resistance made from a cluster of flat powder can be produced at low cost using inexpensive materials. The sheet made of the flake powder described above provides the following effects. First, in a collection of flat powders made of glass, alumina, or hematite, 6-8 insulating metal oxide nanoparticles, which have a hardness lower than that of the flat powder, are stacked on top of each other to bond the flat surfaces of the powder. Because the size of the nanoparticles is more than two orders of magnitude smaller than the particle size of the flat powder, the properties of the sheet are dominated by those of the flake powder. In addition, the bonding layer formed by the collection of nanoparticles forms an insulating layer with high insulation resistance. Therefore, in a sheet made of a collection of insulating flat powders, the metal oxide nanoparticles contribute to further increasing the insulation resistance of the sheet. Second, because the sheet is formed on the bottom of the container in the shape of the bottom, there are no restrictions on the area and shape of the sheet. Furthermore, the above-mentioned eight processes are possible for all flat powders made of glass, alumina, or hematite, regardless of the flatness, shape, or particle size distribution of the flat powder. Therefore, for all flat powders, a sheet can be produced in which the flat surfaces of the flat powder are bonded together with a collection of nanoparticles made of insulating metal oxide. Therefore, this sheet manufacturing method can be used to produce a versatile insulating sheet with high insulation resistance made from a collection of flat powders for flat powders made of glass, alumina, or hematite. As explained above, the sheet made of the aggregate of flat powder produced by this manufacturing method can be formed into a sheet with a large area using a small amount of flat powder, and this sheet becomes an insulating sheet with high insulation resistance.

[0030] The method for producing a sheet made of an aggregate of flat powder described in paragraph 18 is a method for producing a sheet made of an aggregate of inorganic luster pigments in which the surface of flat powder made of glass or aluminum is coated with a coating made of metal or metal oxide, and the method for producing a sheet made of an aggregate of inorganic luster pigments is as follows: The flat powder described in paragraph 18 is an inorganic luster pigment in which the surface of a flat powder made of glass or aluminum is coated with a film made of metal or metal oxide, and the organometallic compound described in paragraph 18 is aluminum octylate, which precipitates aluminum by thermal decomposition. A method for producing a sheet made of an aggregate of inorganic luster pigments, using the inorganic luster pigment as the flat powder described in paragraph 18 and using the aluminum octylate as the organometallic compound described in paragraph 18, and producing a sheet made of an aggregate of inorganic luster pigments in which the flat surfaces of the inorganic luster pigments are bonded to each other via aggregates of aluminum nanoparticles, according to the method for producing a sheet made of an aggregate of flat powders described in paragraph 18. 。

[0031] First, an inorganic bright pigment used in the present invention, in which the surface of a flat powder made of glass or aluminum is coated with a film made of a metal or metal oxide, will be described. There are inorganic luster pigments with excellent luster, in which the surface of flat powder made from glass or aluminum is coated with metals such as gold, silver, or nickel, or metal oxides such as titanium oxide or iron oxide, using electroless plating. Luster pigments made from glass flake powder coated with titanium oxide have been commercialized, with glass flake powder having a plate thickness of 1 μm and an average particle size of 20-80 μm, and reflecting five colors (white, yellow, red, blue, and green) depending on the thickness of the titanium oxide coating. Another product is a luster pigment made from glass flake powder having a plate thickness of 1 to 5 μm and an average particle size of 25-480 μm, coated with a silver coating, which reflects silver. Furthermore, a bright pigment made of glass flake powder coated with iron oxide (hematite consisting of α-Fe2O3) has been commercialized as a bright pigment that reflects five colors (yellow, bronze, copper, and russet) depending on the thickness of the iron oxide coating on glass flake powder with a plate thickness of 1 μm and an average particle size of 30 μm or 80 μm. Another bright pigment has been commercialized as a bright pigment that reflects gold by coating glass flake powder with a plate thickness of 1 μm and an average particle size of 30 μm or 80 μm with a gold coating. Furthermore, a bright pigment made of aluminum flake powder coated with titanium oxide, like the bright pigment made of glass flake powder coated with titanium oxide, has been commercialized as a bright pigment that reflects four colors (yellow, red, orange, and green) depending on the thickness of the titanium oxide coating. The weight of these flat powder inorganic bright pigments is all extremely light. If the flat surfaces of inorganic luster pigment flake powder can be bonded together with a transparent material without damaging the metal or metal oxide coating, a sheet consisting of an aggregate of inorganic luster pigment flake powder can be produced without losing the color reflected from the luster pigment. Furthermore, if multiple types of luster pigments that reflect different colors are used and the flat surfaces of the multiple types of luster pigment flake powder can be bonded together with a transparent material, the color tone emitted by the aggregate of multiple types of luster pigment flake powder can be changed to various colors by combining multiple types of luster pigment. Examples of such transparent nanoparticles include the nickel and aluminum nanoparticles described in paragraph 25. In an aggregate of aluminum nanoparticles, some of the light rays that make up visible light are reflected by the surface of the aggregate of aluminum nanoparticles, emitting a color corresponding to this light, but the aggregate of aluminum nanoparticles is transparent. Furthermore, in an aggregate of nickel nanoparticles, nickel The clusters of nanoparticles are nearly colorless and transparent. The clusters of nanoparticles made of aluminum or nickel maintain their transparency and bond the flat surfaces of the inorganic luster pigment flake powder together. This ensures that the color reflected by the inorganic luster pigment is not lost. Next, the material of the nanoparticles that bond the flat surfaces of the flat powder of the inorganic bright pigment will be described. The coating covering the surface of flat powders made of glass or aluminum is made of metals such as gold, silver, or nickel, or metal oxides such as titanium oxide or iron oxide. Of these coating materials, gold has the lowest hardness, at 2.5 on the Mohs scale, while silver has a Mohs hardness of 2.7. Titanium oxide has a Mohs hardness of 5.5-6, and hematite has a Mohs hardness of 5.5. In contrast, aluminum has a Mohs hardness of 2.9, and nickel has a Mohs hardness of 3.5. Meanwhile, the Young's modulus of gold is 78 GPa, silver 82.7 GPa, aluminum 69 GPa, nickel 204 GPa, titanium oxide 300 GPa, and hematite 160 GPa. When a cluster of nanoparticles contacts the flat surface of a flat powder coated with a metal or metal oxide film, the nanoparticles are small (approximately 10 nm), but the thickness of the thinnest flake powder is 100 times the size of the nanoparticle, and the surface area of ​​the flat powder with the smallest surface area is 2000 times the size of the nanoparticle. Therefore, the contact area between the nanoparticles and the flat surface of the flat powder is extremely small. Furthermore, the contact area between nanoparticles is also extremely small. On the other hand, gold, silver, and aluminum are soft metals with excellent ductility and malleability. Therefore, soft metals have a low Young's modulus. Therefore, when a gold or silver coating contacts a nanoparticle, the localized area of ​​the gold or silver coating at the contact point elastically deforms. This generates frictional heat at the localized area of ​​contact. On the other hand, if the nanoparticles are made of aluminum, aluminum is also a soft metal with a low Young's modulus, so the localized area of ​​the nanoparticles at the contact point elastically deforms. At this time, frictional heat is generated at the localized areas of the contact points. The frictional heat between the two bonds the gold or silver coating and the aluminum nanoparticles. In addition, the Mohs hardness of nickel is higher than that of aluminum, and the Young's modulus of nickel is higher than that of aluminum. Therefore, when the nanoparticles are subjected to stress, the aluminum nanoparticles are more likely to elastically deform than the nickel nanoparticles. For this reason, when the flat surfaces of flat powders covered with a nickel coating are bonded together with a collection of aluminum nanoparticles, the localized areas of the nanoparticles at the contact points undergo elastic deformation preferentially. At this time, frictional heat is generated at the localized areas of the contact points.In contrast, localized contact areas of the nickel coating generate heat without elastic deformation. The frictional heat between them bonds the nickel coating and the aluminum nanoparticles. Furthermore, similar to the nickel coating, when flat surfaces of flat powders coated with a titanium oxide or iron oxide coating are joined by a group of aluminum nanoparticles, localized contact areas of the nanoparticles undergo preferential elastic deformation. At this time, frictional heat is generated at the localized contact areas. In contrast, localized contact areas of the titanium oxide or iron oxide coating generate heat without elastic deformation. The frictional heat between them bonds the titanium oxide or iron oxide coating and the aluminum nanoparticles. When flat surfaces of flat powders coated with a titanium oxide or iron oxide coating are joined by a group of nickel nanoparticles, the Young's modulus of nickel is greater than that of aluminum, which in turn is greater than that of iron oxide, so the amount of elastic deformation of the nickel nanoparticles is smaller than that of the aluminum nanoparticles. Therefore, the possibility of damaging the iron oxide coating cannot be denied. Therefore, when joining flat surfaces of flat powders made of glass or aluminum via a collection of nanoparticles without damaging the coating made of metal or metal oxide, it is preferable to join them using a collection of nanoparticles made of transparent aluminum, which has low hardness and a small Young's modulus. Here, we will explain the effects of a sheet produced according to the method for producing a sheet consisting of a collection of flat powders described in paragraph 18, using flat powders of inorganic lustrous pigments as the flat powders described in paragraph 18, and using nanoparticles of aluminum as the metal or metal oxide nanoparticles described in paragraph 18. First, the substance that connects the flat surfaces of the inorganic luster pigment flake powder is a cluster of aluminum nanoparticles, and aluminum octylate, the raw material for the nanoparticles, is dispersed in methanol to create a liquid phase. Because this liquid has low viscosity and density, by continuously performing the second and third processes, it becomes possible to interpose the methanol dispersion of aluminum octylate in the gaps between the flat surfaces of the inorganic luster pigment flake powder that have been separated into individual sheets. Second, a homogenizer is operated within the container, repeatedly generating shock waves. Because the aluminum octylate methanol dispersion has low viscosity and density, only a small proportion of the shock waves are consumed when exciting the aluminum octylate methanol dispersion, and much of the impact energy is efficiently and repeatedly transmitted to the collection of inorganic luster pigment flake powder. Furthermore, the weight of each flake powder is extremely light. Therefore, even if the flake powder has complex overlapping flat surfaces, when shock waves are applied to the flake powder, it is reliably separated into individual flake powders. As a result, the aluminum octylate methanol dispersion comes into contact with the surface of the coating of all the flake powder, regardless of the material of the inorganic luster pigment flake powder, the material and thickness of the coating, the shape of the flake powder, and the particle size distribution. In addition, the coating on the flat surfaces of all the flat powders is hydrophobic and does not react with the methanol dispersion of aluminum octylate, and the methanol dispersion of aluminum octylate comes into contact with the coating on the flat surfaces. Third, the container has three directions: left and right, front and back, and top and bottom. Impact force Repeatedly add Impact force At this time, since the methanol dispersion of aluminum octylate has low viscosity and density and each flat powder is extremely light, the methanol dispersion of aluminum octylate is mixed with the flat powder. impact The particles move repeatedly in the direction of acceleration. When this phenomenon is repeated in three directions (left and right, front and back, and up and down), the flat powder particles rearrange with the flat surfaces facing up and overlap in the methanol dispersion of aluminum octylate. As a result, the flat powder particles of the inorganic luster pigment spread over the entire bottom surface of the container, and a collection of flat powder particles of the inorganic luster pigment with their flat surfaces overlapping each other via the methanol dispersion of aluminum octylate forms the shape of the bottom surface of the container. Fourth, the individual flat powder particles are stacked together with their flat surfaces interposed in a methanol dispersion of aluminum octylate, so the larger the aspect ratio of the flat powder, the less flat powder is used. Therefore, even if the flat powder is expensive, only a small amount of flat powder is used, making it possible to inexpensively produce sheets made from a collection of flat powder particles. Fifth, methanol is evaporated from the flat powder aggregates, where the flat surfaces of the flat powder are stacked together, via a methanol dispersion of aluminum octylate, causing aggregations of aluminum octylate microcrystals to precipitate in the gaps between the flat surfaces and on the surface of the aggregated flat powder. Furthermore, the entire surface of the aggregated flat powder is evenly compressed. This crushes the microcrystals to about 1 / 5 of their original size, and the crushed crystal aggregates overlap and accumulate at high density in the gaps between the flat surfaces and on the surface of the aggregated flat powder. These crushed aluminum octylate microcrystals, approximately 20 nm in size, become the raw material for aggregations of aluminum nanoparticles, approximately 10 nm in size, that connect the flat surfaces of the flat powder. Sixth, the entire surface of the flaky powder cluster is heated while being uniformly compressed, causing the crushed aluminum octylate microcrystals to thermally decompose. During this process, clusters of aluminum nanoparticles, each approximately 10 nm in size, are deposited simultaneously in high density in the gaps between the flat surfaces of the flaky powder and on the surface of the clusters. Furthermore, the entire surface of the flaky powder cluster is uniformly compressed, and the clusters of aluminum nanoparticles deposited at high density are bonded to the flat surfaces by frictional heat, and the aluminum nanoparticles are also bonded to each other by frictional heat. In other words, because the clusters of aluminum nanoparticles are deposited in a high density, overlapping each other, the compressed nanoparticles have difficulty moving within the clusters. Frictional heat is generated at the contact points of the nanoparticles with the flat surfaces and at the contact points between the nanoparticles. The aluminum nanoparticles are bonded to the flat surfaces by the bonding force generated by the frictional heat, and the aluminum nanoparticles are also bonded to each other by the bonding force generated by the frictional heat. Furthermore, since the nanoparticles are made of aluminum, which has low hardness and a small Young's modulus, when the nanoparticles come into contact with the flat surface, the contact points of the nanoparticles undergo extremely slight elastic deformation, and excessive compressive stress is not applied to the coating surface of the flat surface. As a result, the coating is not damaged. Furthermore, when nanoparticles come into contact with each other, the contact points of the nanoparticles undergo extremely slight elastic deformation, and excessive compressive stress is not applied to the contact points of the nanoparticles. As a result, the nanoparticle clusters are not damaged. Furthermore, when the entire surface of the flat powder cluster is compressed, the nanoparticles are bonded to the flat surface by frictional heat, and after the nanoparticles have bonded to each other by frictional heat, if further compressive stress is applied to the flat powder cluster, a repulsive force is generated in the plate material to which the compressive stress is applied, because the nanoparticles have been miniaturized to the limiting size, and at this point, the compressive stress applied to the flat powder cluster is stopped. Seventh, the inorganic luster pigment flake powder can be used as the flake powder when manufacturing a sheet made of an aggregate of flake powders. The thermal decomposition temperature of aluminum octylate is 290°C, the same as the ambient temperature. On the other hand, the heat resistance of the coating formed on the surface of the inorganic luster pigment flake powder, made of metals such as gold, silver, and nickel, or metal oxides such as titanium oxide and iron oxide, is significantly higher than 290°C. Therefore, a sheet made of an aggregate of flake powders, in which the flat surfaces of the flake powders are bonded together, can be used in harsh environments such as high temperatures, extremely low temperatures, vacuums, and high pressures. Eighth, the flat surfaces of the inorganic luster pigment flaky powder are bonded together with a cluster of aluminum nanoparticles, which are transparent, have low hardness, and a small Young's modulus. Therefore, the flat surfaces of the inorganic luster pigment flaky powder can be bonded together with a cluster of aluminum nanoparticles without damaging the coating made of metal or metal oxide. This allows a sheet made of a cluster of inorganic luster pigment flaky powder to be produced without losing the color reflected from the luster pigment. Furthermore, by using multiple types of luster pigments that reflect different colors and bonding the flat surfaces of the multiple types of luster pigment flaky powder together with a cluster of aluminum nanoparticles, the color tone emitted by the cluster of the multiple types of luster pigment flaky powder can be changed to a variety of colors by combining multiple types of luster pigments. Ninth, aluminum octylate is a general-purpose industrial chemical. Furthermore, since the flat surfaces of the flat powder are bonded together, only a small amount of flat powder is required. Furthermore, all eight processes for bonding the flat surfaces together with clusters of aluminum nanoparticles are simple. Therefore, sheets made of clusters of flat powder of inorganic luster pigment can be manufactured using inexpensive materials at low cost without losing the color reflected from the luster pigment. Furthermore, when the flat surfaces of the flat powder of the inorganic bright pigment are bonded together by a group of aluminum nanoparticles, a further effect can be obtained. First, the surface of the aggregate of inorganic luster pigment flake powder forms irregularities based on the size of the nanoparticles. The total surface area of ​​the irregularities is enormous due to the enormous number of nanoparticles, resulting in a surface similar to a so-called fractal surface. When a liquid droplet comes into contact with the surface of such an aggregate of inorganic luster pigment flake powder, the surface tension of the droplet prevents the liquid from penetrating the irregularities of the nanoparticle size, and the liquid surface of the droplet comes into point contact with the protrusions of the enormous number of nanoparticles. As a result, the surface of the aggregate of inorganic luster pigment flake powder exhibits ultra-water repellency with a contact angle of nearly 180 degrees, resulting in water repellency, oil repellency, and stain resistance. Second, the surface of the aggregates of flat powder of inorganic luster pigments has electrical and thermal conductivity similar to that of the aluminum that makes up the nanoparticles, so aggregates of flat powder of inorganic luster pigments have antistatic properties, electromagnetic wave shielding properties, and heat dissipation properties. As explained above, the surface of the clusters of flat powder of inorganic luster pigment is covered with clusters of aluminum nanoparticles, which provides the sheet with excellent effects based on the size and material of the aluminum nanoparticles that cannot be obtained with inorganic luster pigments. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is an explanatory diagram showing a schematic side view of a sheet made of a collection of flat iron powder particles in which the flat iron powder particles are directly bonded together at their opposing surfaces. DETAILED DESCRIPTION OF THE INVENTION

[0033] Example 1 In this example, a soft magnetic flat powder is used, which is a flattened reduced iron powder. The flat surfaces of the flat iron powder are bonded together via clusters of nickel nanoparticles to produce a sheet made of the aggregate of reduced iron powder. The flat iron powder used was MG150D flat iron powder manufactured by JFE Steel Corporation. This flat iron powder has a large average particle size of 100 μm and an extremely thick thickness of 10-20 μm. This is because, although the particles of reduced iron powder are relatively large, their Vickers hardness is high at 160-200 HV, making them difficult to flatten. First, nickel octylate Ni(CH 1542 g (equivalent to 0.12 moles) of (COO)2 (e.g., a product of Fujifilm Wako Pure Chemical Industries, Ltd.) was dispersed in methanol at a weight ratio of 10%. After this, the methanol dispersion of nickel octylate was filled into a container measuring 20 cm x 20 cm x 1.5 cm (depth), and 40 g of flat iron powder was added to the container. After this, ultrasonic vibrations of 20 kHz were applied to the methanol dispersion of nickel octylate in the container using an ultrasonic homogenizer (e.g., LUH300, a product of Yamato Scientific Co., Ltd.) for 2 minutes. Furthermore, the ultrasonic homogenizer was removed from the container, and three-way vibrations of 0.3 G were applied. impact Acceleration was repeatedly applied to the container, and a mass of flat iron powder was formed in the container, with the flat surfaces of the flat iron powder overlapping each other via the methanol dispersion of nickel octylate. Next, the container was heated to 65°C, and the methanol was evaporated from the methanol dispersion of nickel octylate, causing nickel octylate crystal clusters to precipitate on the surface of the flat iron powder clusters and in the gaps between the flat iron powder surfaces. After this, a plate measuring 20 cm x 20 cm x 2 mm (thickness) was placed over the surface of the flat iron powder clusters, and five 10 kg weights were placed at equal intervals on top of the plate. The container was then placed in a heat treatment device in an air atmosphere, heated to 290°C, and left at 290°C for 1 minute. impact Acceleration was applied, causing the collection of flat iron powder inside the container to be torn off from the container. Next, the surface and side of the sample were observed using an electron microscope. An ultra-low accelerating voltage SEM from JFE Techno-Research Corporation was used as the electron microscope. This device is capable of surface observation at ultra-low accelerating voltages starting from 100V, and has the advantage of being able to directly observe the surface of the sample without forming a conductive coating on it. First, secondary electron beams between 900 and 1000 V were extracted from the reflected electron beam and image-processed. Three flat powder layers, each 10-20 μm thick, were stacked together to form a 20 cm x 20 cm sheet approximately 45 μm thick. Six nanoparticles, each approximately 10 nm in size, were stacked on the surface of the flat powder clusters and in the gaps between the flat powder clusters. Further, energy levels between 900 and 1000 V were extracted from the reflected electron beam and image-processed. The material was observed based on the image density. Since no density difference was observed, it was determined that both the flat powder and the nanoparticles were composed of a single element. Next, the energy and intensity of the characteristic X-rays were image-processed for elemental analysis. It was determined that the flat powder was composed of iron atoms and the nanoparticles were composed of nickel atoms. Therefore, the flat iron powder clusters were joined together via the nickel nanoparticle clusters, forming a sheet. The skin depth of reduced iron powder's electromagnetic waves at 100 kHz is 50 μm. Therefore, a sheet with a thickness of around 45 μm effectively absorbs electromagnetic noise around 100 kHz using a small amount of flat powder made from reduced iron powder. Figure 1 shows a schematic of part of the side of a sheet made of a collection of flat iron powder particles joined together by their flat surfaces via a collection of nickel nanoparticles. 1 is the flat iron powder, and 2 is the nickel nanoparticle. Furthermore, the magnetic shielding performance of the fabricated sheet was evaluated. For comparison, a 45 μm-thick cold-rolled steel sheet was used. A rectangular shielding box with sides of 100 mm was fabricated using both the sheet and the cold-rolled steel sheet. The shielding box was placed inside a Helmholtz coil placed in a magnetically shielded room, and the external magnetic field generated by the Helmholtz coil and the internal magnetic field at the center of the shielding box were measured. The magnetic shielding performance S was evaluated using Equation 5. A magnetic sensor for measuring the magnetic field was installed inside the shielding box through a hole in the shielding box. The sample had a magnetic shielding performance S of 7 dB, which was approximately 3 dB better than that of the cold-rolled steel sheet. These results demonstrate that the fabricated sheet exhibits excellent magnetic shielding performance. (Number 5) S=20·log((external magnetic field) / (internal magnetic field)) Next, the electromagnetic noise absorption performance of the sheet was evaluated. A microstrip line with a length of 220 mm, a width of 30 mm, and a characteristic impedance adjusted to 50 Ω was installed on a board, and the length of the sheet was aligned with the length of the microstrip line, and the sheet was placed so that the centers of the two lines were aligned, creating a magnetic sheet that absorbs noise. After this, S parameters were measured using a network analyzer (Agilent Technologies product N5230A) connected to the microstrip line. The S parameter S due to reflection was 11 and the S-parameter S due to transmission 12 Therefore, the transmission loss in the microstrip line is the amount of electromagnetic wave absorption according to the following formula 6. The measurement results showed that the absorption rate was 12% at 100 kHz, 24% at 800 kHz, and 13% at 10 MHz. The sheet had an absorption rate of more than 12% in the frequency range from 100 kHz to 10 MHz. (Number 6) Reflection amount (dB)=20·log|S 11 | Transmission amount (dB)=20·log|S 12 | Absorption (%) = (1 - |S 11 | 2 -|S 12 | 2 ) x 100

[0034] Example 2 In this example, a sheet consisting of a flat permalloy powder was produced using a flat permalloy powder as the soft magnetic flat powder, with the flat surfaces of the flat permalloy powder bonded together via a cluster of nickel nanoparticles. The flat permalloy powder used was a flat permalloy powder composed of 50% nickel (e.g., a product developed by Sanyo Special Steel). The flat powder had an aspect ratio of 38 and an average particle size of 14 μm. Thus, the average thickness of the flat permalloy powder was extremely thin, and the average particle size was also small. Furthermore, the imaginary part of the complex permeability rose sharply around 100 MHz, peaked at 8.8 at 3.3 GHz, decreased around 4 GHz, and reached a value of 3.5 at 10 GHz. Therefore, in the frequency band of 1-8 GHz, the imaginary part of the complex permeability had a value of 5 or more. In contrast, in a DC magnetic field, the initial relative permeability was 1×10 4 The maximum relative permeability is 1.4 x 10 5 and has a large value. First, 21 g (corresponding to 0.08 moles) of the nickel octylate used in Example 1 was dispersed in methanol at a weight ratio of 10%. Then, the methanol dispersion of nickel octylate was filled into a container measuring 12 cm x 12 cm x 2 cm (depth), and 18 g of flat permalloy powder was added to the container. Then, ultrasonic vibrations of 20 kHz were applied to the methanol dispersion of nickel octylate in the container for 2 minutes using the ultrasonic homogenizer used in Example 1. Then, the ultrasonic homogenizer was removed from the container, and three-way vibrations of 0.2 G were applied. impact Acceleration was repeatedly applied to the container, and a mass of flat permalloy powder was formed in the container, with the flat surfaces of the flat permalloy powder overlapping each other via the methanol dispersion of nickel octylate. Next, the container was heated to 65°C, and the methanol was evaporated from the methanol dispersion of nickel octylate, causing nickel octylate crystal clusters to precipitate on the surfaces of the flat permalloy powder clusters and in the gaps between the flat surfaces of the flat permalloy powder. After this, a plate measuring 12 cm x 12 cm x 3 cm (thickness) was placed over the surface of the flat iron powder clusters, and five 6 kg weights were placed at equal intervals on top of the plate. The container was then placed in a heat treatment device in an air atmosphere, heated to 290°C, and left at 290°C for 1 minute. impact Acceleration was applied, causing the collection of flat iron powder inside the container to be torn off from the container. Next, similar to Example 1, the surface and sides of the sheet were observed with an electron microscope. A 0.4-0.5 μm thick material was found to be stacked into 10 layers, with nanoparticles of approximately 10 nm in size interposed between them. Because this material was composed of nickel and iron atoms, it was a permalloy. Furthermore, because the nanoparticles were composed of nickel atoms, they were nickel nanoparticles. Since the skin depth of permalloy at 1 GHz is 5.0 μm, a 4-5 μm thick sheet effectively absorbs electromagnetic noise near 1 GHz using a small amount of flat powder made of permalloy. Furthermore, the magnetic shielding performance of the sheet was evaluated using the same method as in Example 1. For comparison, a 5 μm-thick sheet made of 47% nickel permalloy was used. As in Example 1, rectangular parallelepiped shielding boxes with sides of 100 mm were created using the sheet and a permalloy sheet. The sample had a magnetic shielding performance S value of 40 dB, which was about 5 dB better than the 47Ni permalloy sheet. As a result, the sample provided excellent magnetic shielding effect. Next, the sheet's electromagnetic noise absorption performance was evaluated using the same method as in Example 1. The absorption rate was 8% at 1 GHz, 10% at 3 GHz, and 8% at 6.8 GHz. Therefore, the sample had an absorption rate of 8% or more in the frequency band from 1 GHz to 7 GHz. However, the amount of electromagnetic wave absorption was low. This is due to the small average particle size of the flattened permalloy powder and the low flatness.

[0035] Example 3 In this example, flat sendust powder is used as the soft magnetic flat powder, and a sheet is produced consisting of an aggregate of flat sendust powder in which the flat surfaces of the flat sendust powder are bonded together via an aggregate of nickel nanoparticles. The Sendust flake powder is a Sanyo Special Steel High Permeability Type A product. It has a relatively large average particle size of less than 50 μm, a thickness of approximately 1 μm, and an aspect ratio of nearly 50. Compared to conventional Sendust, this flake powder contains trace amounts of nickel and reduced silicon content, which facilitates flattening and increases the particle size of the flake powder, significantly improving its complex permeability. The imaginary part of the complex permeability has a value of over 60 in the 10-70 MHz frequency band and a value of over 30 in the 3-100 MHz frequency band. Compared to the Permalloy flake powder used in Example 2, the flake powder has a larger particle size and is thicker. Furthermore, the flake ratio is large, and the imaginary part of the complex permeability exceeds 10 times the value in the 3-100 MHz frequency band. The real part of the complex permeability also has a large value of 200 in the 1-3 MHz frequency band. Therefore, it is effective in suppressing electromagnetic noise in the frequency band above 3 MHz. However, its magnetic permeability in a DC magnetic field is two orders of magnitude smaller than that of the permalloy used in Example 2, so its magnetic shielding effect is low. The skin depth of the flat sendust powder at 3 MHz is 20 μm. First, 42 g (equivalent to 0.12 moles) of nickel octylate used in Example 1 was dispersed in methanol at a weight ratio of 10%. Note that the flat powder of sendust is thicker and has a larger average particle size than flat permite. After this, the methanol dispersion of nickel octylate was filled into a container measuring 20 cm x 20 cm x 1.5 cm (depth), and 40 g of flat sendust powder was added to the container. After this, ultrasonic vibrations of 20 kHz were applied to the methanol dispersion of nickel octylate in the container for 2 minutes using the ultrasonic homogenizer device used in Example 1. Furthermore, the ultrasonic homogenizer device was removed from the container, and three-directional vibrations of 0.3 G were applied. impact Acceleration was repeatedly applied to the container, and an aggregate of the flat sendust powder was formed in the container, with the flat surfaces of the flat sendust powder overlapping each other via the methanol dispersion of nickel octylate. Next, the container was heated to 65°C, and methanol was evaporated from the methanol dispersion of nickel octylate, causing clusters of nickel octylate crystals to precipitate on the surfaces of the clusters of flat sendust powder and in the gaps between the flat surfaces of the flat sendust powder. After this, a plate measuring 20 cm x 20 cm x 2 mm (thickness) was placed over the surface of the clusters of flat sendust powder, and five 8 kg weights were placed at equal intervals on top of the plate. The container was then placed in a heat treatment device in an air atmosphere, heated to 290°C, and left at 290°C for 1 minute. impact Acceleration was applied, causing the mass of flat Sendust powder inside the container to be torn off from the container. Next, similar to Example 1, the surface and sides of the sheet were observed with an electron microscope. A 1 μm-thick material was found to be stacked into 20 layers, interspersed with nanoparticles approximately 10 nm in size. This material was mostly composed of iron atoms, followed by silicon atoms, aluminum atoms, and traces of nickel atoms, making it closer to super sendust than sendust. Furthermore, since the nanoparticles were composed of nickel atoms, they were nickel nanoparticles. Since the skin depth of flat sendust powder at 3 MHz is 20 μm, a 20 μm-thick sheet effectively absorbs electromagnetic noise around 3 MHz using a small amount of flat sendust powder. Furthermore, the electromagnetic noise absorption performance of the prepared sheet was evaluated using the same method as in Example 2. The absorption rate was 28% at 3 MHz, 38% at 10 MHz, 42% at 20 MHz, 38% at 50 MHz, and 28% at 100 MHz. Therefore, the prepared sheet had an absorption rate of 28% or more in the frequency band of 3-100 MHz. Compared to Example 4, the electromagnetic wave absorption rate was significantly increased. This is due to the larger particle size and larger flatness of the sendust flat powder compared to the permalloy flat powder.

[0036] Example 4 In this example, flat powders made from three types of alloys whose imaginary parts of complex permeability have peak values ​​in different frequency bands are used, and a sheet is produced from an assembly of the three types of flat powders, with the flat surfaces of the three types of flat powders joined together via clusters of nickel nanoparticles. The three types of alloy flat powders were prepared by adding flat powder of silicon steel containing 3% silicon and flat powder of electromagnetic stainless steel to the flat powder of permalloy used in Example 2. Flat powder made of silicon steel with 3% silicon (for example, a product developed by Sanyo Special Steel) has an aspect ratio of 34 and an average particle size of 9 μm. Furthermore, in contrast to the flat powder of permalloy in Example 2, the imaginary part of the complex permeability has the required magnitude in the high frequency band. That is, it gradually increases from around 10 MHz, has a value of 2.3 at 1 GHz, intersects with the imaginary part of the complex permeability of permalloy at 4.7 GHz, shows a peak value of 8.7 at 5.9 GHz, gradually decreases from around 6.3 GHz, has a value of 5.9 at 10 GHz, and has a value of 3.7 at 12 GHz. Therefore, above 4.7 GHz, the imaginary part of the complex permeability is larger than that of permalloy flat powder. Flat powder made of electromagnetic stainless steel with iron added with 7% chromium, 1% silicon, and 1.6% aluminum (for example, a product developed by Sanyo Special Steel) has an aspect ratio of 29 and an average particle size of 12 μm. The imaginary part of the complex permeability increases sharply from around 10 MHz, reaching a value of 3.4 at 1 GHz, intersecting with the imaginary part of silicon steel with 3% silicon at 4.2 GHz, showing a peak value of 7.5 at 4.8 GHz, and gradually decreasing from around 5.5 GHz, remaining at 4.8 even at 10 GHz and reaching a value of 3.1 at 12 GHz. Therefore, when three types of flat powder—Permalloy flat powder, 3% silicon silicon steel flat powder, and 3% silicon stainless steel flat powder—are used to form a sheet by randomly overlapping the flat surfaces of the three types of flat powder, the imaginary part of the complex permeability of the sheet becomes the sum of the imaginary parts of the complex permeability of the three types of flat powder, improving its ability to absorb electromagnetic noise in the intermediate frequency band from 2 to 8 GHz. In particular, this improves its ability to absorb electromagnetic noise in the frequency band from 3.3 GHz, where the imaginary part of the complex permeability of Permalloy peaks, to 4.8 GHz, where the imaginary part of the complex permeability of 3% silicon silicon steel peaks. First, 32 g (equivalent to 0.09 moles) of the nickel octylate used in Example 1 was dispersed in methanol at a weight ratio of 10%. After this, the methanol dispersion of nickel octylate was filled into a container measuring 15 cm x 15 cm x 1.5 cm (depth). Next, 8 g of flat powder of permalloy, 7 g of flat powder of silicon steel, and 15 g of flat powder of electromagnetic stainless steel were added to the container. After this, ultrasonic vibrations of 20 kHz were applied to the methanol dispersion of nickel octylate in the container for 2 minutes using the ultrasonic homogenizer used in Example 1. Furthermore, the ultrasonic homogenizer was removed from the container, and three-way vibrations of 0.3 G were applied. impact Acceleration was repeatedly applied to the container, and a collection of flat powders made of the three types of alloys was created in the container, with the flat surfaces of the flat powders overlapping each other through a methanol dispersion of nickel octylate. Next, the container was heated to 65°C, and the methanol was evaporated from the methanol dispersion of nickel octylate, causing clusters of nickel octylate crystals to precipitate on the surface of the cluster of flat powder made of the three types of alloys and in the gaps between the flat surfaces of the flat powder made of the three types of alloys. After this, a plate measuring 15 cm x 15 cm x 2 mm (thickness) was placed over the surface of the cluster of flat powder made of the three types of alloys, and five 6 kg weights were placed at equal intervals on top of the plate. The container was then placed in a heat treatment chamber in an air atmosphere, heated to 290°C, and left at 290°C for 1 minute. impactAcceleration was applied, and a collection of flat powders made up of three types of alloys inside the container was pulled away from the container. Next, the surface and sides of the sheet were observed under an electron microscope in the same manner as in Example 1. It was found that 10 layers of material with a thickness of 0.4-0.6 μm were stacked together, with a collection of nanoparticles with a size of around 10 nm in between. Furthermore, the electromagnetic noise absorption performance of the fabricated sheet was evaluated using the same method as in Example 1. The absorption rate was 8% at 1 GHz, 10% at 3.3 GHz, 9% at 4.7 GHz, 10% at 5.9 GHz, and 8% at 10 GHz. As a result, the absorption rate was 8% or more over the wide frequency band of 1-10 GHz. However, the amount of electromagnetic wave absorption was low. This is due to the smaller average particle size and lower flatness of the three alloys compared to the flat powder of sendust used in Example 3. Note that the combination of soft magnetic flat powders made of multiple types of alloys is not limited to Example 4. In other words, by combining flat powders made of multiple types of alloys and adjusting the amount of each flat powder used so that the imaginary part of the complex permeability has a constant value over a wide frequency band, the flat powders made of multiple types of alloys, in which the flat surfaces overlap and bond, exhibit the characteristics of the imaginary part of the complex permeability of each flat powder, which is added according to the amount of each flat powder used. As a result, a sheet that absorbs electromagnetic noise over a wide frequency band can be realized.

[0037] Example 5 In this example, flake copper powder is used to produce a sheet consisting of an aggregate of flake copper powder, in which the flat surfaces of the flake copper powder are bonded together via aggregates of copper nanoparticles. The flake copper powder used was MS-800 manufactured by Fukuda Metal Foil and Powder Co., Ltd. The particle size distribution of this flake copper powder is such that more than 4% of the flake powder is larger than 75 μm, more than 25% of the flake powder is larger than 45 μm, and more than 75% of the flake powder is smaller than 45 μm. The thickness is around 0.5 μm, so the aspect ratio is large. The apparent density is 0.6-1.0 g / cm. 3 The raw material for copper nanoparticles is copper octylate, Cu(C7H15 COO)2 (e.g., a product of Mitsuwa Pharmaceutical Co., Ltd.) was used. First, 12 g (equivalent to 0.035 moles) of copper octylate was dispersed in methanol at a weight ratio of 10%. Then, the methanol dispersion of copper octylate was filled into a container measuring 8 cm x 8 cm x 2 cm (depth), and 9 g of flake copper powder was added to the container. Then, ultrasonic vibrations of 20 kHz were applied to the methanol dispersion of copper octylate in the container for 2 minutes using the ultrasonic homogenizer used in Example 1. Then, the ultrasonic homogenizer was removed from the container, and three-way vibrations of 0.2 G were applied. impact Acceleration was repeatedly applied to the container, and an aggregate of the flake copper powder was formed in the container, with the flat surfaces of the flake copper powder overlapping each other via the methanol dispersion of copper octylate. Next, the container was heated to 65°C, and the methanol was evaporated from the methanol dispersion of copper octylate, causing copper octylate crystals to precipitate on the surfaces of the copper flake powder clusters and in the gaps between the flat surfaces of the copper flake powder. After this, a plate measuring 8 cm x 8 cm x 2.5 mm (thickness) was placed over the surface of the copper flake powder clusters, and five 4 kg weights were placed at equal intervals on top of the plate. The container was then placed in a heat treatment device in an air atmosphere, heated to 290°C, and left at 290°C for 1 minute. impact Acceleration was applied, causing the collection of flake copper powder inside the container to be torn off from the container. Next, the surface and side of the sheet were observed under an electron microscope in the same manner as in Example 1. Copper flake powder with a thickness of about 0.5 μm was stacked into six layers, with aggregations of copper nanoparticles with a size of about 10 nm in between. Furthermore, the electrical resistance of the sample was measured using a DC resistance meter (for example, Tsuruga Electric Co., Ltd. DC resistance meter model 356H). Terminals were attached to four points on the sample, and a DC current was passed through the sample in different directions. The voltage was measured twice at the two inner terminals, and the resistance value calculated by dividing the difference between these two voltage values ​​by the current value measured at the two outer terminals showed a volume resistivity close to that of copper. Therefore, the fabricated sample is a sheet with excellent thermal and electrical conductivity.

[0038] Example 6 In this example, flake copper powder is used to produce a sheet consisting of an aggregate of flake copper powder particles, the planes of which are bonded together via aggregates of nickel nanoparticles. The flake copper powder used in Example 5 was used. The raw material for the nickel nanoparticles was nickel octylate Ni(CH 15 COO)2 (e.g., a product of Fujifilm Wako Pure Chemical Industries, Ltd.) was used. First, 12 g (corresponding to 0.035 moles) of the nickel octylate used in Example 1 was dispersed in methanol at a weight ratio of 10%. Then, the methanol dispersion of nickel octylate was filled into a container measuring 8 cm x 8 cm x 2 cm (depth), and 9 g of flake copper powder was added to the container. Then, ultrasonic vibrations of 20 kHz were applied to the methanol dispersion of nickel octylate in the container for 2 minutes using the ultrasonic homogenizer used in Example 1. Then, the ultrasonic homogenizer was removed from the container, and three-way vibrations of 0.2 G were applied. impact Acceleration was repeatedly applied to the container, and an aggregate of the flake copper powder was formed in the container, with the flat surfaces of the flake copper powder overlapping each other via the methanol dispersion of nickel octylate. Next, the container was heated to 65°C, and methanol was evaporated from the methanol dispersion of nickel octylate, causing clusters of nickel octylate crystals to precipitate on the surfaces of the clusters of flake copper powder and in the gaps between the flat surfaces of the flake copper powder. After this, a plate measuring 8 cm x 8 cm x 3 mm (thickness) was placed over the surface of the clusters of flake copper powder, and five 4 kg weights were placed at equal intervals on top of the plate. The container was then placed in a heat treatment device in an air atmosphere, heated to 290°C, and left at 290°C for 1 minute. impact Acceleration was applied, causing the collection of flake copper powder inside the container to be torn off from the container. Next, the surface and side of the sheet were observed under an electron microscope in the same manner as in Example 1. Copper flake powder with a thickness of about 0.5 μm was stacked into six layers, with clusters of nickel nanoparticles with a size of about 10 nm in between. Furthermore, the electrical resistance of the sample was measured using the DC resistance meter used in Example 5. The sample exhibited a volume resistivity close to that of copper. Furthermore, the sample exhibited a sheet color with a reddish, dark yellow-brown tinge that is characteristic of copper. Therefore, the fabricated sample has excellent thermal and electrical conductivity, as well as the characteristic reddish, dark yellow-brown tinge that is characteristic of copper.

[0039] Example 7 In this example, alumina flake powder is used as a flat powder with excellent insulating and lubricating properties, and a sheet is produced consisting of a cluster of alumina flake powder bonded together via clusters of magnesium oxide nanoparticles. The alumina flake powder (BMF-B, a product of Kawai Lime Industry Co., Ltd.) has an aspect ratio of approximately 40, an average particle size of 9 μm, and a density of 3.98 g / cm. 3 The scaly boehmite powder (product BMF) is heat treated at a temperature of 500°C or higher to obtain alumina scaly powder similar in shape to boehmite. First, 22 g (equivalent to 0.07 moles) of magnesium caprylate Mg(CH3(CH2)6COO)2 (imported product) was dispersed in methanol at a weight ratio of 10%. After this, the methanol dispersion of magnesium caprylate was filled into a container measuring 11 cm x 11 cm x 2 cm (depth), and 40 g of alumina flake powder was added to the container. Thereafter, ultrasonic vibrations of 20 kHz were applied to the methanol dispersion of nickel octylate in the container for 2 minutes using the ultrasonic homogenizer used in Example 1. The ultrasonic homogenizer was then removed from the container, and three-way vibrations of 0.3 G were applied. impact Acceleration was repeatedly applied to the container, and an aggregate of the alumina flake powder was formed in the container, with the flat surfaces of the alumina flake powder overlapping each other via the methanol dispersion of magnesium caprylate. Next, the container was heated to 65°C, and the methanol was evaporated from the methanol dispersion of magnesium caprylate, causing magnesium caprylate crystals to precipitate on the surface of the alumina flake powder clusters and in the gaps between the flat surfaces of the alumina flake powder. After this, a plate measuring 11 cm x 11 cm x 3 mm (thickness) was placed over the surface of the alumina flake powder clusters, and five 5 kg weights were placed at equal intervals on top of the plate. The container was then placed in a heat treatment device in an air atmosphere, heated to 290°C, and left at 290°C for 1 minute. impact Acceleration was applied, causing the alumina flakes inside the container to be torn off from the container. Next, the surface and side of the sheet were observed under an electron microscope in the same manner as in Example 1. It was found that 10 layers of flat alumina powder with a thickness of 0.2-0.3 μm were stacked, with aggregates of magnesium oxide nanoparticles with a size of around 10 nm in between. After this, when the surface resistance of the sample was measured at several points with an insulation resistance meter, the needle swung out and the resistance value was greater than 100 MΩ. Next, the static and dynamic friction coefficients of the multiple surfaces of the sample were measured using a measuring device (a friction coefficient measuring device consisting of a Shimadzu Autograph AGS-X tabletop precision universal testing instrument). The static friction coefficient was 0.15±0.03, and the dynamic friction coefficient was 0.10±0.02. Both friction coefficients were small.

[0040] Example 8 In this example, colored flake powder is used as the flat powder, and the flat surfaces of the flake powder are bonded together via clusters of aluminum nanoparticles to produce a sheet consisting of a cluster of colored flake powder. Colored flake powder (Metashine, a product of Nippon Sheet Glass Co., Ltd.) in which glass flake powder is coated with titanium oxide was used as the colored flake powder. Equal amounts of two types of glass flake powder, red (E025RR) and blue (E025RB), were mixed. The colored flake powder had a thickness of 0.5 μm, an average particle size of 25 μm, and a density of 2.6 g / cm. 3 is. First, aluminum octoate Al(CH 15 23 g (equivalent to 0.05 mol) of (COO)3 (imported product) was dispersed in methanol at a weight ratio of 10%. The methanol dispersion of aluminum octoate was then filled into a 12 cm x 12 cm x 2 cm (depth) container, and 65 g of colored flake powder was added to the container. Thereafter, ultrasonic vibrations of 20 kHz were applied to the methanol dispersion of aluminum octylate in the container for 2 minutes using the ultrasonic homogenizer used in Example 1. The ultrasonic homogenizer was then removed from the container, and a three-way vibration of 0.2 G was applied. impact Acceleration was repeatedly applied to the container, and an aggregate of colored flake powder was formed in the container, with the flat surfaces of the colored flake powder overlapping each other via the methanol dispersion of aluminum octylate. Next, the container was heated to 65°C, and methanol was evaporated from the methanol dispersion of aluminum octylate, causing aluminum octylate crystal clusters to precipitate on the surface of the colored flake powder clusters and in the gaps between the flat surfaces of the colored flake powder. After this, a plate measuring 12 cm x 12 cm x 3 cm (thickness) was placed over the surface of the colored flake powder clusters, and five 4 kg weights were placed at equal intervals on top of the plate. The container was then placed in a heat treatment device in an air atmosphere, heated to 290°C, and left at 290°C for 1 minute. impact Acceleration was applied, causing the collection of flake copper powder inside the container to be torn off from the container. First, the spectral reflectance of the sample was measured using a spectrophotometer (CM-700d, manufactured by Konica Minolta Japan, Inc.) The spectral reflectance was highest around 470 nm, which emits a blue color, and around 700 nm, which emits a red color. Next, the side of the sample was observed and analyzed using an electron microscope in the same manner as in Example 1. As a result, the flat surfaces of the glass flake powder were found to be stacked into 10 layers of glass flake powder with a thickness of 0.5 μm, with a cluster of aluminum nanoparticles with a size of about 10 nm in between. On the other hand, the base material of the flat powder is transparent, flat glass flake powder, and the flat surfaces of this glass flake powder are bonded together via clusters of transparent aluminum nanoparticles, so the coating emits a reddish-purple color that combines a strong luster, transparency, and high brightness. From the above results, it was found that the flat surfaces of colored glass flake powder coated with titanium oxide were stacked and bonded together in 10 layers to form a sheet made of glass flake powder. This sheet had excellent colorability. 31 By using flake powders colored in various colors as described in the paragraph or a plurality of types of colored flake powders, colored sheets emitting various colors can be formed. [Explanation of symbols]

[0041] 1. Reduced iron powder 2. Nickel nanoparticles

Claims

1. A method for producing a sheet consisting of an assembly of flat powders made of any one of metals, alloys, metal oxides, and inorganic compounds excluding tin and zinc, in which the flat surfaces of the flat powders are bonded together via an assembly of nanoparticles of the metal or metal oxide, comprises: An organometallic compound that precipitates a metal or metal oxide upon thermal decomposition is dispersed in a molecular state in methanol, and the methanol dispersion of the organometallic compound is filled into a container. Thereafter, a mass of flat powder made of any one of metals, alloys, metal oxides, and inorganic compounds excluding tin and zinc is weighed out to a weight less than the weight obtained by multiplying the weight of the methanol by the ratio of the density of the methanol to the density of the flat powder used. The weighed mass of flat powder is then poured into the container and stirred in the methanol dispersion of the organometallic compound. Furthermore, a homogenizer is placed in the container and operated within the container to mix the methanol of the organometallic compound. shock waves are repeatedly applied to the collection of flat powder through the methanol dispersion liquid, the collection of flat powder is separated into individual flat powder sheets through the methanol dispersion liquid of the organometallic compound, and the separated flat powder sheets are covered with the methanol dispersion liquid of the organometallic compound; thereafter, the homogenizer device is removed from the container; further, impact accelerations are repeatedly applied to the container in three directions, front-to-back, left-to-right, and up-to-down, and finally an impact acceleration is applied in the up-to-down direction, causing the methanol dispersion liquid of the organometallic compound to enter into the gaps between the flat surfaces of the flat powder; and the collection of flat powder, in which the flat surfaces of the flat powder overlap each other, is formed on the bottom surface of the container in the shape of the bottom surface through the methanol dispersion liquid of the organometallic compound. Thereafter, the container is heated to the boiling point of methanol, and methanol is evaporated from the methanol dispersion of the organometallic compound, causing clusters of fine crystals of the organometallic compound having a size smaller than 100 nm to precipitate in the gaps between the flat surfaces of the flat powder and on the surface of the cluster of flat powder.Furthermore, a plate material covering the entire surface of the cluster of flat powder is placed over the entire surface of the cluster of flat powder, and the entire surface of the plate material is evenly compressed, crushing the fine crystals of the organometallic compound into fine crystals having a size of approximately 20 nm, which is approximately 1 / 5 of the size. Furthermore, a compressive load is applied evenly to the entire surface of the plate material, and the temperature of the container is raised to the thermal decomposition temperature of the organometallic compound, causing the thermal decomposition of the fine crystals of the organometallic compound. As a result, clusters of nanoparticles of metal or metal oxide having a size of about 10 nm are deposited in layers in the gaps between the flat surfaces of the flat powder and on the surfaces of the clusters of flat powder. Further, the clusters of nanoparticles are compressed, and the clusters of nanoparticles are bonded to the flat surfaces of the flat powder by frictional heat, and the nanoparticles are also bonded to each other by frictional heat. As a result, the clusters of nanoparticles bonded by frictional heat A sheet consisting of a collection of flat powder in which the flat surfaces of the flat powder are joined together via balls is produced within the container in the shape of the bottom of the container; then, impact acceleration is applied to the container in three directions (front and back, left and right, and up and down), the sheet consisting of the collection of flat powder is peeled off from the bottom of the container, and the sheet is removed from the container; this is a method for producing a sheet consisting of a collection of flat powder in which the flat surfaces of the flat powder, made of one type of material selected from the group consisting of metals excluding tin and zinc, alloys, metal oxides, and inorganic compounds, are joined together via collections of metal or metal oxide nanoparticles.

2. The method for producing a sheet made of a collection of flat powder according to claim 1 is a method for producing a sheet made of a collection of soft magnetic flat powder, and the method for producing a sheet made of a collection of soft magnetic flat powder is as follows: A method for producing a sheet consisting of a collection of soft magnetic flat powder, wherein the flat powder described in claim 1 is a soft magnetic flat powder made of one of the following materials: iron, permalloy, silicon steel, sendust, or electromagnetic stainless steel; the organometallic compound described in claim 1 is nickel octylate, which precipitates nickel upon thermal decomposition; the soft magnetic flat powder made of any one of the above materials is used as the flat powder described in claim 1, and the nickel octylate is used as the organometallic compound described in claim 1; and a method for producing a sheet consisting of a collection of soft magnetic flat powder, wherein the flat surfaces of the soft magnetic flat powder made of one type of material are joined together via collections of nickel nanoparticles, according to the method for producing a sheet consisting of a collection of soft magnetic flat powder described in claim 1.

3. The method for producing a sheet made of an aggregate of soft magnetic flat powders according to claim 2 is a method for producing a sheet made of an aggregate of soft magnetic flat powders of a plurality of types of alloys, and the method for producing a sheet made of an aggregate of soft magnetic flat powders of a plurality of types of alloys is as follows: The soft magnetic flat powder according to claim 2 is a soft magnetic flat powder made of a plurality of types of alloys excluding iron, and the frequency characteristics of the imaginary part of the complex permeability of the soft magnetic flat powder made of the plurality of types of alloys are different from each other in the soft magnetic flat powder made of each of the alloys. The frequency characteristics of the imaginary part of the complex permeability of the soft magnetic flat powder made of each of the alloys have different frequency ranges in which the imaginary parts of the complex permeability complement each other. The soft magnetic flat powder made of the plurality of types of alloys is used as the flat powder according to claim 1, and nickel octylate according to claim 2 is used as the organometallic compound according to claim 1. A method for producing a sheet made of a collection of soft magnetic flat powders of a plurality of types of alloys, in which the flat surfaces of the soft magnetic flat powders of the plurality of types of alloys are bonded together via a collection of nickel nanoparticles, according to the method for producing a sheet made of a collection of soft magnetic flat powders of a plurality of types of alloys.

4. The method for producing a sheet made of a collection of flat powders according to claim 1 is a method for producing a sheet made of a collection of flake powders of metals or alloys, and the method for producing a sheet made of a collection of flake powders of metals or alloys is as follows: A method for producing a sheet consisting of an assembly of metal or alloy flake powder, wherein the flat powder described in claim 1 is a flake powder of metal or alloy made of one of silver, copper, brass, nickel, and aluminum, and the organometallic compound described in claim 1 is a metal octylate compound of one of copper octylate, aluminum octylate, and nickel octylate, and the flake powder of metal or alloy made of one of the materials is used as the flat powder described in claim 1, and the metal octylate compound of one of the materials is used as the organometallic compound described in claim 1, and a sheet consisting of an assembly of flake powder of metal or alloy made of one of the materials is produced according to the method for producing a sheet consisting of an assembly of flat powder described in claim 1, wherein the flat surfaces of the flake powder of metal or alloy made of one of the materials are bonded together via an assembly of nanoparticles made of copper, aluminum, or nickel.

5. The method for producing a sheet made of an aggregate of flat powder according to claim 1 is a method for producing a sheet made of an aggregate of insulating flat powder made of metal oxide or inorganic compound, and the method for producing a sheet made of an aggregate of insulating flat powder made of metal oxide or inorganic compound is as follows: The flat powder described in claim 1 is an insulating flat powder made of a metal oxide or an inorganic compound made of one of glass, alumina, or hematite, and the organometallic compound described in claim 1 is a complex made of a carboxylic acid metal compound that precipitates an insulating metal oxide by thermal decomposition, the insulating metal oxide having a hardness lower than that of the insulating flat powder made of the metal oxide or the inorganic compound. The insulating flat powder made of a metal oxide or an inorganic compound made of one of the materials is used as the flat powder described in claim 1, and the complex made of the carboxylic acid metal compound is used as the organometallic compound described in claim 1. A method for producing a sheet made of an assembly of insulating flat powder made of a metal oxide or an inorganic compound, in which the flat surfaces of the insulating flat powder made of the metal oxide or the inorganic compound are bonded together via a collection of nanoparticles made of an insulating metal oxide having a hardness lower than that of the insulating flat powder.

6. The method for producing a sheet made of an aggregate of flat powders according to claim 1 is a method for producing a sheet made of an aggregate of inorganic luster pigments, in which the surface of flat powder made of glass or aluminum is coated with a coating made of metal or metal oxide, and the method for producing a sheet made of an aggregate of inorganic luster pigments is as follows: A method for producing a sheet consisting of a collection of inorganic luster pigments, wherein the flat powder described in claim 1 is an inorganic luster pigment in which the surface of a flat powder made of glass or aluminum is coated with a coating made of metal or metal oxide, and the organometallic compound described in claim 1 is aluminum octylate, which precipitates aluminum by thermal decomposition, and the inorganic luster pigment is used as the flat powder described in claim 1, and the aluminum octylate is used as the organometallic compound described in claim 1, and a sheet consisting of a collection of inorganic luster pigments in which the flat surfaces of the inorganic luster pigments are joined together via collections of nanoparticles made of aluminum is produced according to the method for producing a sheet consisting of a collection of flat powders described in claim 1.

Images