Surface-coated modified metal powder and method for producing the same

Abstract

The application discloses a kind of surface coating modified metal powder preparation methods, and method steps specifically include: in the surface of metal particle is coated with ethyl silicate, forms ethyl silicate coated powder;The ethyl silicate coated powder is mixed with organic acid, water, forms reaction slurry, carries out solid-liquid separation, obtains solid powder;The solid powder is dried, and the surface coating modified metal powder is obtained.The preparation method of the application is first to the surface of metal particle with dry grinding mode is treated with ethyl silicate, then by chemical reaction treatment obtains silica modified metal powder, improves the dispersibility of powder in aqueous slurry.Simultaneously, the metal particle treated with silica improves the chemical corrosion resistance of its powder, which is beneficial to the long-term use of wave-absorbing materials.The wave-absorbing material prepared using the modified metal powder has low dielectric constant, which meets the dielectric constant requirement of electromagnetic compatibility wave-absorbing material for manganese-zinc ferrite sheet.

Description

Technical Field

[0001] This invention relates to a metal powder and its preparation method, and more particularly to a surface-coated modified metal powder and its preparation method. Background Technology

[0002] With the development of technology, more and more wireless devices are integrated into artificial intelligence equipment, leading to increasingly prominent electromagnetic interference between these devices. Electromagnetic compatibility (EMC) testing and capability evaluation of these devices are receiving increasing attention. Domestic EMC anechoic chamber manufacturing technology and electromagnetic testing capabilities are continuously improving. The shift towards white-material EMC absorbing materials is both urgent and crucial.

[0003] Currently, the composite layout of electromagnetic compatibility (EMC) absorbing materials and manganese-zinc ferrite sheets is the mainstream direction for constructing high-performance EMC anechoic chambers. The return loss of the absorbing materials used in this approach is closely related to the dielectric constant of the absorbing materials in the low-frequency range of 30MHz to 300MHz. White conductive metal oxides are the core component in the production of white EMC absorbing agents. Replacing conductive carbon black with white metal oxides and using impregnation or coating processes to produce absorbing materials with a dielectric constant >2 results in poor absorption performance between the material and the ferrite. Summary of the Invention

[0004] The purpose of this invention is to provide a surface-modified metal powder and its preparation method for preparing white electromagnetic compatibility (EMC) absorbing materials, thereby solving the problem of poor dielectric constant matching between existing water-based slurries and ferrites in white EMC absorbing materials produced by impregnation or coating methods.

[0005] This invention provides the following solution:

[0006] A method for preparing surface-coated modified metal powder, specifically comprising:

[0007] Ethyl silicate is coated onto the surface of metal particles to form ethyl silicate coated powder;

[0008] The ethyl silicate-coated powder is mixed with organic acid and water to form a reaction slurry, and then solid-liquid separation is performed to obtain solid powder.

[0009] The solid powder is dried to obtain a surface-coated modified metal powder.

[0010] Furthermore, the metal particles are indium tin oxide or conductive titanium dioxide.

[0011] Furthermore, the organic acid is one or more of formic acid, acetic acid, and propionic acid.

[0012] Furthermore, the step of mixing the ethyl silicate-coated powder with organic acid and water specifically includes: mixing metal particles and an aqueous solution of ethyl silicate, grinding them in a planetary mill, and carrying out an in-situ reaction to obtain ethyl silicate-coated powder.

[0013] Furthermore, the mass concentration of the ethyl silicate aqueous solution is 5-100 g / L, 100-500 g of metal particles are added to every 100 mL of ethyl silicate aqueous solution, the weight ratio of grinding balls to grinding material is 10-20:1, the grinding temperature is 20-40℃, and the grinding time is 12-24 h.

[0014] Furthermore, the weight ratio of organic acid to ethyl silicate coated powder is 0.1 to 0.5:1.

[0015] Furthermore, the weight ratio of water to organic acid is 6 to 10:1.

[0016] Furthermore, the mixing of the ethyl silicate-coated powder with organic acid and water is specifically carried out by magnetic stirring at 40-60°C for 12-24 hours to allow for reaction, followed by filtration of the solid powder, and rinsing the solid powder with deionized water 2-3 times for later use.

[0017] Furthermore, the process of drying the solid powder specifically involves drying the separated solid powder at a temperature of 80–105°C for 4–8 hours to obtain surface-modified metal powder.

[0018] A surface-coated modified metal powder, wherein the surface-coated modified metal powder is prepared by a metal powder preparation method.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The preparation method of this invention first coats the metal particles with ethyl silicate. This not only allows for uniform adsorption of ethyl silicate on the surface of the metal particles, thereby improving the dispersion uniformity of the final powder material, but also, through the reaction of ethyl silicate with organic acid and water, forms a silica layer coating the surface of the metal particles, thus reducing the electromagnetic parameters of the metal particles. The silica coating layer improves the chemical corrosion resistance of the metal particles and extends the service life of the white electromagnetic compatibility absorbing material. This surface-modified metal powder has a low dielectric constant, meeting the dielectric constant requirements for synergistic matching of manganese-zinc ferrite sheets. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a flowchart of a method for preparing surface-coated modified metal powder. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Best practice: such as Figure 1 The method flow for preparing surface-coated modified metal powder shown specifically includes:

[0025] Step S1: Coating the surface of metal particles with ethyl silicate to form ethyl silicate-coated powder;

[0026] Specifically, the metal particles are indium tin oxide or conductive titanium dioxide.

[0027] Step S2: The ethyl silicate coated powder is mixed with organic acid and water to form a reaction slurry, and then solid-liquid separation is performed to obtain solid powder.

[0028] Specifically, the organic acid is one or more of formic acid, acetic acid, and propionic acid.

[0029] For example, metal particles and an aqueous solution of ethyl silicate are mixed and ground in a planetary mill to carry out an in-situ reaction, thereby obtaining ethyl silicate-coated powder.

[0030] For example, the mass concentration of the ethyl silicate aqueous solution is 5-100 g / L, 100-500 g of metal particles are added to every 100 ml of ethyl silicate aqueous solution, the weight ratio of grinding balls to grinding material is 10-20:1, the grinding temperature is 20-40℃, and the grinding time is 12-24 h.

[0031] Specifically, the mixing method involves magnetic stirring at 40–60°C for 12–24 hours to carry out the reaction, filtering out the solid powder, rinsing the solid powder with deionized water 2–3 times, and then setting it aside.

[0032] For example, the weight ratio of organic acid to ethyl silicate coated powder is 0.1 to 0.5:1.

[0033] For example, the weight ratio of water to organic acid is 6 to 10:1.

[0034] Step S3: Dry the solid powder to obtain surface-coated modified metal powder.

[0035] Specifically, the separated solid powder is dried at a temperature of 80–105°C for 4–8 hours to obtain surface-modified metal powder.

[0036] The present invention also discloses a surface-coated modified metal powder, which is prepared by the metal powder preparation method disclosed in the above embodiments.

[0037] For the purpose of simplicity, the method steps disclosed in the above embodiments are described as a series of actions. However, those skilled in the art should understand that the embodiments of the present invention are not limited to the described order of actions, because according to the embodiments of the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily essential to the embodiments of the present invention.

[0038] Any process or method description, whether flowcharted or otherwise, may be understood to be performed and implemented not in the order shown or discussed, including in a substantially simultaneous manner or in reverse order of the functions involved, as will naturally be understood by those skilled in the art when practicing embodiments of the present invention.

[0039] Example 1:

[0040] (1) 300g of indium tin oxide powder (0.5μm thick, radial dimension of 5~10μm) was added to 100ml of ethyl silicate aqueous solution, wherein the concentration of ethyl silicate aqueous solution was 5g / l, and the powder was ground at 25℃ for 12h to obtain ethyl silicate coated powder.

[0041] (2) Mix the coated powder with 100g acetic acid and 900g deionized water, stir magnetically at 50°C for 24 hours, and then filter.

[0042] (3) The filtered powder was dried in a constant temperature drying oven at 80℃ to obtain silicon dioxide modified indium tin oxide powder.

[0043] Example 2:

[0044] (1) 300g of indium tin oxide powder (0.5μm thick, radial dimension of 5~10μm) was added to 100ml of ethyl silicate aqueous solution, wherein the concentration of ethyl silicate aqueous solution was 10g / l, and the powder was ground at 25℃ for 12h to obtain ethyl silicate coated powder.

[0045] (2) Mix the coated powder with 100g acetic acid and 900g deionized water, stir magnetically at 50°C for 24 hours, and then filter.

[0046] (3) The filtered powder was dried in a constant temperature drying oven at 80℃ to obtain silicon dioxide modified indium tin oxide powder.

[0047] Example 3:

[0048] (1) 300g of indium tin oxide powder (0.5μm thick, radial dimension of 5~10μm) was added to 100ml of ethyl silicate aqueous solution, wherein the concentration of ethyl silicate aqueous solution was 20g / l, and the powder was ground at 25℃ for 12h to obtain ethyl silicate coated powder.

[0049] (2) Mix the coated powder with 100g acetic acid and 900g deionized water, stir magnetically at 50°C for 24 hours, and then filter.

[0050] (3) The filtered powder was dried in a constant temperature drying oven at 80℃ to obtain silicon dioxide modified indium tin oxide powder.

[0051] Example 4:

[0052] (1) 300g of indium tin oxide powder (0.5μm thick, radial dimension of 5~10μm) was added to 100ml of ethyl silicate aqueous solution, wherein the concentration of ethyl silicate aqueous solution was 30g / l, and the powder was ground at 25℃ for 12h to obtain ethyl silicate coated powder.

[0053] (2) Mix the coated powder with 100g acetic acid and 900g deionized water, stir magnetically at 50°C for 24 hours, and then filter.

[0054] (3) The filtered powder was dried in a constant temperature drying oven at 80℃ to obtain silicon dioxide modified indium tin oxide powder.

[0055] Example 5:

[0056] (1) 300g of indium tin oxide powder (0.5μm thick, radial dimension of 5~10μm) was added to 100ml of ethyl silicate aqueous solution, wherein the concentration of ethyl silicate aqueous solution was 50g / l, and the powder was ground at 25℃ for 12h to obtain ethyl silicate coated powder.

[0057] (2) Mix the coated powder with 100g acetic acid and 900g deionized water, stir magnetically at 50°C for 24 hours, and then filter.

[0058] (3) The filtered powder was dried in a constant temperature drying oven at 80℃ to obtain silicon dioxide modified indium tin oxide powder.

[0059] Example 6:

[0060] (1) 300g of indium tin oxide powder (0.5μm thick, radial dimension of 5~10μm) was added to 100ml of tetraethyl orthosilicate aqueous solution, wherein the concentration of tetraethyl orthosilicate aqueous solution was 80g / l, and the powder was ground at 25℃ for 12h to obtain tetraethyl orthosilicate coated powder.

[0061] (2) Mix the coated powder with 100g acetic acid and 900g deionized water, stir magnetically at 50°C for 24 hours, and then filter.

[0062] (3) The filtered powder was dried in a constant temperature drying oven at 80℃ to obtain silicon dioxide modified indium tin oxide powder.

[0063] Performance characterization:

[0064] The powders prepared in the above examples were characterized as follows:

[0065] Density: Powder density tester, model: Ruike Instruments FT-100A

[0066] Dielectric constant tester: Agilent 16453A dielectric test fixture

[0067] Vector Network Analyzer: Model Agilent E8363C PNA Microwave Network Analyzer

[0068] The characterization results are shown in Table 1:

[0069]

[0070] Note: The filling ratio is the ratio of product powder to paraffin wax during the microwave absorption performance test. The optimal filling ratio and product thickness are different for different products to achieve the best microwave absorption performance.

[0071] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art and should not be interpreted in an idealized or overly formal sense unless specifically defined.

[0072] It should be noted that certain terms are used in this specification and claims to refer to specific elements. Those skilled in the art will understand that different manufacturers or producers may use different terms to refer to the same element. This specification and claims do not distinguish elements based on differences in terminology, but rather on differences in function.

[0073] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, any of the embodiments claimed in the claims can be used in any combination of embodiments of the invention.

[0075] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0076] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0077] All features disclosed in this specification, or steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps. Any feature disclosed in this specification, unless specifically stated otherwise, may be replaced by other equivalent or similar features. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features. Throughout this specification, the same reference numerals indicate the same elements.

[0078] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing surface-coated modified metal powder, characterized in that, Specifically, it includes: Ethyl silicate is coated onto the surface of metal particles to form ethyl silicate coated powder; The ethyl silicate-coated powder is mixed with organic acid and water to form a reaction slurry, and then solid-liquid separation is performed to obtain solid powder. The solid powder is dried to obtain a surface-coated modified metal powder. The metal particles are indium tin oxide or conductive titanium dioxide. The process of mixing the ethyl silicate-coated powder with organic acid and water specifically includes: mixing metal particles and an aqueous solution of ethyl silicate, grinding them in a planetary mill, and carrying out an in-situ reaction to obtain ethyl silicate-coated powder; The mass concentration of the ethyl silicate aqueous solution is 5-100 g / L. 100-500 g of metal particles are added to every 100 mL of ethyl silicate aqueous solution. The weight ratio of grinding balls to grinding material is 10-20:

1. The grinding temperature is 20-40℃ and the grinding time is 12-24 h. The weight ratio of organic acid to ethyl silicate coated powder is 0.1–0.5:1; The weight ratio of water to organic acid is 6 to 10:

1.

2. The method for preparing surface-coated modified metal powder according to claim 1, characterized in that, The organic acid is one or more of formic acid, acetic acid, and propionic acid.

3. The method for preparing surface-coated modified metal powder according to claim 1, characterized in that, The process of mixing the ethyl silicate-coated powder with organic acid and water is as follows: the mixing method involves magnetic stirring at 40-60°C for 12-24 hours to carry out the reaction, filtering out the solid powder, rinsing the solid powder with deionized water 2-3 times, and then setting it aside for later use.

4. The method for preparing surface-coated modified metal powder according to claim 1, characterized in that, The process of drying the solid powder specifically involves drying the separated solid powder at a temperature of 80–105°C for 4–8 hours to obtain surface-modified metal powder.

5. A surface-coated modified metal powder, characterized in that, The surface-coated modified metal powder is prepared by the metal powder preparation method according to any one of claims 1 to 4.

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