Soft magnetic composite material plate and method of manufacturing soft magnetic composite material plate

Abstract

To provide a soft magnetic composite material plate indicating Pi lower than a conventional Fe based amorphous alloy plate or Fe-based nano crystal alloy plate, and a method of manufacturing the soft magnetic composite material plate.SOLUTION: A soft magnetic composite material plate comprises a soft magnetic Fe-based alloy plate and an electric insulation coating which is formed on a surface of the soft magnetic Fe-based alloy plate. The soft magnetic Fe-based alloy plate is an Fe-based amorphous alloy plate or an Fe-based nano crystal alloy plate. The electric insulation coating contains a lead-free glass composition and has a linear expansion coefficient which is less than a linear expansion coefficient of the soft magnetic Fe-based alloy plate. The glass composition has a softening point equal to or lower than a temperature at which a fine structure of the soft magnetic Fe-based alloy plate is maintained.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technology of soft magnetic materials, and more particularly to a soft magnetic composite plate exhibiting low core loss and a method for manufacturing the soft magnetic composite plate. [Background technology]

[0002] Laminated cores, which are made by laminating multiple sheets of soft magnetic material (e.g., 0.01 to 3 mm thick), such as pure iron sheets or steel sheets, are widely used in electrical machinery (e.g., rotating electrical machines and transformers). From the perspective of protecting the global environment, the application fields of electrical machinery using soft magnetic materials have been expanding in recent years, and as a result, there has been an increasing demand for higher output and smaller size of these electrical machinery. In other words, there is a growing demand for increasing the power density (power output per unit mass, W / kg) of these electrical machinery.

[0003] When considering a rotating electric machine as an electromechanical device, its output is proportional to the product of the rotation speed and torque during operation, so increasing either the rotation speed or the torque can increase output. Torque is proportional to the product of the magnetic flux density and the current value. To increase the magnetic flux density, it is desirable to use a soft magnetic material that achieves a high saturation magnetic flux density Bs. Various methods of controlling the composition and microstructure of soft magnetic materials are used to increase Bs.

[0004] On the other hand, when increasing the rotation speed during operation, the conversion efficiency between electrical energy and magnetic energy is important, and reducing the loss (iron loss Pi) in the soft magnetic material plate becomes a challenge. Pi is the sum of hysteresis loss and eddy current loss, and a small coercive force Hc is desirable to reduce hysteresis loss, while increasing electrical resistance and thinning the plate are effective in reducing eddy current loss.

[0005] For these reasons, in order to increase the output density of the electromechanical device, it is desirable for the soft magnetic material to have both a high Bs and a low Pi.

[0006] Fe-Si alloy-based electrical steel sheets are currently widely used as a material that offers a good balance between a relatively high Bs and a relatively low Pi. Meanwhile, Fe (iron)-based amorphous alloy sheets and Fe-based nanocrystalline alloy sheets have recently attracted attention as materials that exhibit a lower Pi than Fe-Si alloy-based electrical steel sheets. Furthermore, because electromechanical devices that use soft magnetic materials have a wide variety of applications and sizes, active research has been conducted into the development of technologies for the stable production of soft magnetic materials to meet the various design requirements of these devices.

[0007] For example, in Patent Document 1 (JP 2022-113111), the alloy composition is represented by the formula (Fe 1-x A x ) a Si b B c Cu d M e where A is at least one of Ni and Co, and M is one or more selected from the group consisting of Nb, Mo, V, Zr, Hf, and W, and the atomic percentages are 82.4≦a≦86, 0.2≦b≦2.4, 12.5≦c≦15.0, 0.05≦d≦0.8, 0.4≦e≦1.0, and 0≦x≦0.1. The soft magnetic alloy ribbon has a structure in which crystal grains having a grain size of 60 nm or less exist in an amorphous phase, and has a saturation magnetic flux density of 1.74 T or more and an iron loss at 1 kHz and 1 T of 25 W / kg or less.

[0008] According to Patent Document 1, it is possible to obtain a soft magnetic alloy ribbon having a high saturation magnetic flux density and low iron loss, and a method for manufacturing the same. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2022-113111 Summary of the Invention [Problem to be solved by the invention]

[0010] As mentioned above, there is a growing demand for higher power density (W / kg) of electromechanical devices. Recently, increasing the rotation speed and frequency during operation has been promoted as a means of increasing the output of such devices. However, increasing the rotation speed and frequency poses serious problems such as energy loss and reduced efficiency due to the Pi of soft magnetic materials.

[0011] The present invention has been made to solve the above-mentioned problems. The primary object of the present invention is to provide a soft magnetic composite sheet that exhibits a lower Pi than conventional Fe-based amorphous alloy sheets and Fe-based nanocrystalline alloy sheets, and a method for manufacturing the same. [Means for solving the problem]

[0012] (I) One aspect of the present invention is a soft magnetic composite plate having a soft magnetic Fe-based alloy plate and an electrically insulating coating formed on the surface of the soft magnetic Fe-based alloy plate, the soft magnetic Fe-based alloy plate is an Fe-based amorphous alloy plate or an Fe-based nanocrystalline alloy plate; the electrical insulating coating contains a lead-free glass composition and has a linear expansion coefficient less than that of the soft magnetic Fe-based alloy plate, The glass composition has a softening point equal to or lower than a temperature at which the microstructure of the soft magnetic Fe-based alloy plate is maintained. The present invention provides a soft magnetic composite plate characterized by the above-mentioned.

[0013] In the present invention, the linear expansion coefficient of the glass composition is defined as the average linear expansion coefficient from room temperature to the glass transition temperature Tg (see FIG. 4 described later), and the linear expansion coefficient of the soft magnetic Fe-based alloy plate is defined as the average linear expansion coefficient from room temperature to the first crystallization temperature (see FIG. 3 described later).

[0014] In the present invention, the following improvements and modifications can be freely combined and added to the soft magnetic composite material plate (I) according to the present invention. (i) The glass composition has, when the nominal components are expressed in terms of oxides, It contains 40% by mass or more and 70% by mass or less of V2O5 (vanadium oxide) and 10% by mass or more and 35% by mass or less of P2O5 (phosphorus oxide), and the total of the V2O5 and the P2O5 is 50% by mass or more and 98% by mass or less, Contains two or more selected from the group consisting of BaO (barium oxide), Sb2O3 (antimony oxide), WO3 (tungsten oxide), ZnO (zinc oxide), K2O (potassium oxide), Fe2O3 (iron oxide), TeO2 (tellurium oxide), Ag2O (silver oxide), and Li2O (lithium oxide) in a total amount of 2% by mass or more and 50% by mass or less, The remainder is unavoidable impurities. (ii) the electrical insulating coating contains 75% by volume or less of a filler material of oxide particles; The filler is one or more of the group consisting of SiO2 (silicon oxide), ZrO2 (zirconium oxide), Al2O3 (aluminum oxide), Nb2O5 (niobium oxide), ZrSiO4 (zirconium silicate), Zr2(WO4)(PO4)2 (zirconium tungstate phosphate), 2MgO·2Al2O3·5SiO2 (cordierite), 3Al2O3·2SiO2 (mullite), and LiAlSiO4 (eucryptite). (iii) The linear expansion coefficient of the electrical insulating coating is less than 10 ppm / °C, and the softening point of the glass composition is 500°C or lower. (iv) The soft magnetic Fe-based alloy plate has a tensile strain in the in-plane direction in the range of 1 μST to 1000 μST.

[0015] (II) Another aspect of the present invention is a method for producing the soft magnetic composite plate described above, a soft magnetic Fe-based alloy plate preparation step of preparing a soft magnetic Fe-based alloy plate; a glass paste preparation step of preparing a glass paste that is a base for the electrical insulating coating; a soft magnetic composite material precursor forming step of forming a soft magnetic composite material precursor by applying the glass paste to at least one main surface of the soft magnetic Fe-based alloy plate; an electrical insulating film forming step of forming the electrical insulating film by heat treating the soft magnetic composite material precursor; The present invention provides a method for manufacturing a soft magnetic composite plate, which is characterized by having the following features:

[0016] In the present invention, the following improvements and modifications can be freely combined and added to the above-described method (II) for producing a soft magnetic composite plate according to the present invention. (v) the heat treatment in the electrically insulating coating forming step includes a drying process of heating to and maintaining a temperature of 120°C or higher and 200°C or lower, and a firing process of heating to and maintaining a temperature 20°C to 50°C higher than the softening point of the glass composition, The maximum temperature of the firing process is lower than the peak crystallization temperature of the glass composition and lower than the second crystallization temperature of the soft magnetic Fe-based alloy plate. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a soft magnetic composite sheet that exhibits a lower Pi than conventional Fe-based amorphous alloy sheets and Fe-based nanocrystalline alloy sheets, and a method for producing the same.

[0018] Problems, configurations, and effects other than those described above will become clear from the description of the embodiments below. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view showing a structural example of a soft magnetic composite plate according to the present invention; [Figure 2] 1 is an example of a chart (DTA curve) obtained during the temperature rise process of differential thermal analysis (DTA) for an Fe-based amorphous alloy plate used in the present invention. [Figure 3] 1 is an example of a chart (DTA curve) obtained during the temperature rise process of DTA for a glass composition used in the present invention. [Figure 4] 1 is a flow diagram showing an outline of a method for manufacturing a soft magnetic composite plate according to the present invention. [Figure 5] FIG. 1 is a flow chart showing an outline of a method for manufacturing a laminated core using a soft magnetic composite plate according to the present invention. [Figure 6A] FIG. 1 is a schematic perspective view showing an example of a stator of a rotating electric machine. [Figure 6B] FIG. 2 is an enlarged cross-sectional schematic view of a slot region of the stator. DETAILED DESCRIPTION OF THE INVENTION

[0020] [Basic concept of the present invention] The present inventors focused on the low Pi exhibited by Fe-based amorphous alloy sheets and Fe-based nanocrystalline alloy sheets and studied techniques for further reducing Pi. In the course of this research, they discovered that applying in-plane tensile strain to the Fe-based alloy sheets reduces Pi. However, they also found that treatment to impart in-plane tensile strain to the Fe-based alloy sheets (e.g., heating above a certain temperature) can cause undesired crystallization and grain coarsening, making it impossible to maintain the original microstructure, resulting in a significant increase in Pi.

[0021] Therefore, the present inventors have conducted extensive research into a technique for applying in-plane tensile strain to an Fe-based amorphous alloy sheet or an Fe-based nanocrystalline alloy sheet while maintaining the inherent microstructure of the alloy. As a result, they have found that the object can be achieved by forming a composite material sheet in which a predetermined lead-free glass composition is formed on the surface of the Fe-based alloy sheet as an electrical insulating coating. The present invention was completed based on this finding.

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the specific embodiments described, and can be appropriately combined with or improved on known techniques without departing from the technical concept of the invention.

[0023] [Soft magnetic composite plate of the present invention] Fig. 1 is a cross-sectional view showing an example of the structure of a soft magnetic composite plate according to the present invention. As shown in Fig. 1, a soft magnetic composite plate 10 according to the present invention is a composite plate in which an electrically insulating coating 2 is formed on at least one surface of a soft magnetic Fe-based alloy plate 1.

[0024] The soft magnetic Fe-based alloy plate 1 is made of an Fe-based amorphous alloy plate or an Fe-based nanocrystalline alloy plate. In other words, the soft magnetic Fe-based alloy plate 1 is an alloy plate having a microstructure made of an Fe-based amorphous alloy phase and / or an Fe-based nanocrystalline alloy phase.

[0025] The Fe-based amorphous alloy plate and the Fe-based nanocrystalline alloy plate used in the present invention are not particularly limited, and conventional ones can be used as appropriate. In the present invention, the Fe-based nanocrystalline alloy plate basically means an alloy plate in which an Fe-based nanocrystalline alloy phase is finely dispersed in a matrix of an Fe-based amorphous alloy phase, but it may also be an alloy plate composed only of an Fe-based nanocrystalline alloy phase.

[0026] The electrical insulating coating 2 is a layer of a lead-free glass composition. The glass composition has a softening point equal to or lower than the temperature at which the microstructure of the soft magnetic Fe-based alloy sheet 1 is maintained, and has a linear expansion coefficient lower than that of the soft magnetic Fe-based alloy sheet 1. When the electrical insulating coating 2 is formed in a state where the temperature is raised to an appropriate temperature, a compressive stress is applied to the electrical insulating coating 2 during cooling due to the difference in linear expansion coefficient, and a tensile stress can be applied to the soft magnetic Fe-based alloy sheet 1.

[0027] Research by the present inventors has revealed that Pi can be significantly reduced by applying a tensile strain within the elastic deformation range in the in-plane direction to the soft magnetic Fe-based alloy plate 1. On the other hand, Pi increases when a tensile strain in the plastic deformation range is applied to the soft magnetic Fe-based alloy plate 1. The amount of strain applied to the soft magnetic Fe-based alloy plate 1 is preferably in the range of 1 μST to 1000 μST (where ST means the amount of strain), more preferably in the range of 10 μST to 500 μST, and even more preferably in the range of 20 μST to 200 μST.

[0028] Figure 2 shows an example of a chart (DTA curve) obtained during the temperature increase process of differential thermal analysis (DTA) for the Fe-based amorphous alloy sheet used in the present invention. As shown in Figure 2, two large exothermic peaks are observed when the Fe-based amorphous alloy sheet is heated. The first exothermic peak is considered to be an exothermic reaction in which partial crystallization begins from the amorphous phase (an exothermic reaction in which the nanocrystalline alloy phase begins to nucleate and crystallize), and the peak temperature is defined as the first crystallization temperature. The second exothermic peak is considered to be an exothermic reaction in which the original amorphous phase is completely crystallized and the nanocrystalline alloy phases begin to coalesce and coarsen, and the peak temperature is defined as the second crystallization temperature.

[0029] The specific values of these first crystallization temperature and second crystallization temperature will naturally vary depending on the alloy composition and microstructure of the Fe-based amorphous alloy sheet or Fe-based nanocrystalline alloy sheet, but the first crystallization temperature is usually about 400 to 550°C, and the second crystallization temperature is usually about 500 to 600°C.

[0030] It is known that an Fe-based nanocrystalline alloy sheet can be obtained by heat-treating an Fe-based amorphous alloy sheet at a temperature between the first crystallization temperature and the second crystallization temperature, but if the heat-treatment is performed at a temperature higher than the second crystallization temperature, the Pi of the alloy sheet increases rapidly.

[0031] 3 is an example of a chart (DTA curve) obtained during the temperature rise process of DTA for the glass composition used in the present invention. As shown in FIG. 3, the onset temperature of the first endothermic peak is taken as the glass transition point Tg (viscosity = 10 13.3 The peak temperature of the first endothermic peak is the sag point Td (viscosity = 10 11.0 The peak temperature of the second endothermic peak is the softening point Ts (viscosity = 10 7.65 The peak temperature of the first exothermic peak is defined as the crystallization peak temperature Tcp. These temperatures are determined by the tangent method.

[0032] A glass composition with lower characteristic temperatures Tg, Td, and Ts is more likely to soften and flow at low temperatures, allowing the electrical insulating coating 2 to be formed at low temperatures. From the standpoint of workability and temperature controllability, it is desirable to form the electrical insulating coating 2 at a temperature that is approximately 20 to 50°C higher than Ts. On the other hand, if the glass composition crystallizes, the softening and flow properties are significantly impaired and the adhesion of the coating is also greatly reduced, so the coating must be formed at a temperature below Tcp.

[0033] For these reasons, the glass composition constituting the electrical insulating coating 2 preferably has a characteristic temperature such that the temperature difference between Ts and Tcp is approximately 20 to 50°C or more. It is also preferable to use a glass composition having a Ts that is 20°C or more lower than the second crystallization temperature of the soft magnetic Fe-based alloy plate 1. More specifically, the glass composition used in the present invention preferably has a Ts of 500°C or less, more preferably 450°C or less, and even more preferably 420°C or less.

[0034] Since it is undesirable for the electrical insulating coating of the soft magnetic composite plate to soften and flow when the electromechanical device is used, it is preferable that the Ts of the glass composition be higher than the temperature at which the electromechanical device is used when using the soft magnetic composite plate 10 of the present invention. For example, if the operating temperature of the electromechanical device is 150°C, it is preferable that the Ts of the glass composition be higher than 150°C.

[0035] Electrical equipment used in Europe is subject to the RoHS Directive (a European Union directive restricting the use of certain hazardous substances in electrical and electronic equipment, which came into effect on July 1, 2006). Glass compositions containing PbO (lead oxide) as a major component were once widely used as glass compositions with low Ts, but Pb is designated as a prohibited substance under the RoHS Directive, making them incompatible with the RoHS Directive. Therefore, the soft magnetic composite plate of the present invention utilizes a glass composition that does not contain Pb (lead-free glass composition).

[0036] The lead-free glass composition used in the present invention, when expressed as nominal oxide components, contains 40 to 70 mass% V2O5 and 10 to 35 mass% P2O5, the total of which is 50 to 98 mass%. It also contains 2 to 50 mass% of two or more elements selected from the group consisting of BaO, Sb2O3, WO3, ZnO, KO, Fe2O3, TeO2, Ag2O, and Li2O, with the balance consisting of unavoidable impurities. Note that "lead-free" in the present invention means that the glass composition may contain the aforementioned substances prohibited by the RoHS Directive within the specified range.

[0037] In the lead-free glass composition used in the present invention, V2O5 is a component that contributes to lowering the glass softening flow temperature. P2O5 is a component that can form the glass skeleton and also contributes to suppressing crystallization of glass. BaO, Sb2O3, WO3, ZnO, K2O, and Fe2O3 are components that contribute to improving the moisture and water resistance of glass and suppressing crystallization. TeO2 and Ag2O, like V2O5, are components that contribute to lowering the glass softening flow temperature. Li2O is a vitrifying component that contributes to improving adhesion and adhesion.

[0038] By controlling the above components and their contents, a lead-free glass composition having a desired characteristic temperature can be obtained.

[0039] In order to impart tensile strain in the in-plane direction to the soft magnetic Fe-based alloy plate 1, the electrical insulating coating 2 preferably has a linear expansion coefficient smaller than that of the soft magnetic Fe-based alloy plate 1 (usually 10 ppm / °C or higher). The lead-free glass composition used in the present invention is an oxide glass, and therefore has a linear expansion coefficient smaller than that of the soft magnetic Fe-based alloy plate 1, which is a metallic material. However, if the difference between the linear expansion coefficients is too small, sufficient tensile strain cannot be imparted.

[0040] Therefore, from the viewpoint of controlling the linear expansion coefficient of the electrical insulating coating 2, a filler may be mixed into the lead-free glass composition. Naturally, mixing a filler is not essential. As the filler, oxide particles are preferred from the viewpoint of compatibility with oxide glass. For example, one or more selected from the group consisting of SiO2, ZrO2, Al2O3, Nb2O5, ZrSiO4, Zr2(WO4)(PO4)2, 2MgO·2Al2O3·5SiO2, 3Al2O3·2SiO2, and LiAlSiO4 can be suitably used. The oxide particles are preferably spherical (e.g., with a minor axis / major axis ratio of 0.8 or more).

[0041] The average particle size of the filler is preferably 0.1 μm to 10 μm, more preferably 0.5 μm to 5 μm. When a filler is mixed, the mixing ratio is preferably 75 vol% or less, more preferably 70 vol% or less, and even more preferably 5 vol% to 70 vol%.

[0042] Forming the electrical insulating coating 2 by mixing a filler into a lead-free glass composition has the advantage of being able to control the linear expansion coefficient of the electrical insulating coating 2 and also the viscosity during softening and flow. In addition, controlling the average particle size and mixing ratio of the filler has the advantage of making it easier to control the spacing between the soft magnetic Fe-based alloy plates 1 / thickness of the electrical insulating coating 2 when stacking the soft magnetic Fe-based alloy plates 1.

[0043] [Method of manufacturing soft magnetic composite material plate] Fig. 4 is a flow diagram showing an outline of a method for manufacturing a soft magnetic composite material plate according to the present invention. As shown in Fig. 4, a soft magnetic Fe-based alloy plate preparation step S1 for preparing a soft magnetic Fe-based alloy plate 1 and a glass paste preparation step S2 for preparing a glass paste that will be the basis for the electrical insulating coating 2 are performed. The order of steps S1 and S2 does not matter.

[0044] Next, a soft magnetic composite material precursor formation step S3 is performed in which the glass paste prepared in step S2 is applied to at least one main surface of the soft magnetic Fe-based alloy plate 1 prepared in step S1 to form a soft magnetic composite material precursor.

[0045] Next, an electrical insulating film forming step S4a is performed in which the soft magnetic composite material precursor is heat treated to form the electrical insulating film 2. Through these steps, the soft magnetic composite material plate 10 according to the present invention is obtained.

[0046] Fig. 5 is a flow diagram showing an outline of a method for manufacturing a laminated core using a soft magnetic composite plate according to the present invention. As shown in Fig. 5, first, steps S1 to S3 are performed in the same manner as in the method for manufacturing a soft magnetic composite plate shown in Fig. 4.

[0047] Next, an iron core precursor forming step S5a is performed in which a plurality of soft magnetic composite material precursors are stacked to form an iron core precursor.

[0048] Next, an iron core formation step S4b is performed in which the iron core precursor is heat treated to form an electrical insulating coating 2, and the soft magnetic Fe-based alloy plates 1 are joined together via the electrical insulating coating 2 to form a laminated iron core. Through these steps, a laminated iron core using the soft magnetic composite material plate 10 according to the present invention is obtained.

[0049] Although not shown, another method for manufacturing a laminated iron core may involve first manufacturing a soft magnetic composite plate 10 according to the present invention, then performing a soft magnetic composite laminate formation step S5b in which a plurality of soft magnetic composite plates 10 are laminated to form a soft magnetic composite laminate, and then performing a core formation step S4c in which the soft magnetic composite laminate is heat treated to soften, flow, and harden the electrical insulating coating 2 again, and the soft magnetic Fe-based alloy plates 1 are joined together to form a laminated iron core.

[0050] Each step will be described in more detail.

[0051] Step S1 is a step of preparing a soft magnetic Fe-based alloy plate 1. This step is not particularly limited as long as the desired soft magnetic Fe-based alloy plate 1 can be prepared, and includes procuring it from a commercially available Fe-based amorphous alloy plate or Fe-based nanocrystalline alloy plate.

[0052] Furthermore, as part of this process, a soft magnetic Fe-based alloy plate shaping process may be performed to process the soft magnetic Fe-based alloy plate 1 into a desired shape. There are no particular limitations on the method for shaping the soft magnetic Fe-based alloy plate 1, and conventional metal processing methods (e.g., punching) can be used as appropriate.

[0053] Step S2 is a step of preparing a glass paste that is the base of the electrical insulating coating 2. The glass paste is obtained by mixing a resin binder and a solvent with a powder of the lead-free glass composition described above or a glass frit obtained by mixing the powder with the filler described above.

[0054] When a filler is mixed with the glass frit, as described above, the lead-free glass composition is preferably 25% by volume or more and 80% by volume or less, and the filler is preferably 20% by volume or more and 75% by volume or less. As a resin binder for the glass paste, for example, nitrocellulose can be preferably used. As a solvent for the glass paste, for example, butyl carbitol acetate or α-terpineol can be preferably used. The mixing ratio of the resin binder and the solvent can be appropriately adjusted taking into consideration the workability when applying the glass paste.

[0055] Step S3 is a step of forming a soft magnetic composite material precursor by applying the glass paste prepared in step S2 to at least one main surface of the soft magnetic Fe-based alloy plate 1 prepared in step S1. There are no particular limitations on the application method as long as the thickness of the applied glass paste film (e.g., on the order of μm) can be controlled, and for example, a doctor blade method or the like can be suitably used.

[0056] Step S4a is a step of heat-treating the soft magnetic composite material precursor prepared in step S3 to form an electrical insulating coating 2. The heat treatment pattern may include, for example, a drying process in which the coating is heated and maintained at 120 to 200°C to dry out moisture, binder components, and solvent components, followed by a firing process in which the coating is heated and maintained at a temperature 20 to 50°C higher than the Ts of the lead-free glass composition used. The maximum temperature in the firing process is lower than the Tcp of the lead-free glass composition used and lower than the second crystallization temperature of the soft magnetic Fe-based alloy plate 1 used.

[0057] After the electrical insulating film 2 is formed by the firing process, when it is cooled, due to the difference in linear expansion coefficients, compressive stress is applied to the electrical insulating film 2 and tensile stress is applied to the soft magnetic Fe-based alloy plate 1. Ceramic materials are generally brittle to tensile stress but are very strong to compressive stress, so they can maintain / fix the soft magnetic Fe-based alloy plate 1 in a state where tensile strain is applied in the in-plane direction.

[0058] In order to adjust the tensile strain of the soft magnetic Fe-based alloy plate 1, the heat treatment may be performed in a state where a tensile stress is applied to the soft magnetic Fe-based alloy plate 1.

[0059] Step S5a is a step of forming an iron core precursor by stacking multiple sheets of the soft magnetic composite material precursor prepared in step S3. There are no particular limitations on the method of stacking the soft magnetic composite material precursor, and any conventional stacking method for laminated iron cores can be used as appropriate.

[0060] Step S4b is a step of forming a laminated iron core by heat treating the iron core precursor prepared in step S5a to form an electrical insulating coating 2 and joining soft magnetic Fe-based alloy plates 1 together via the electrical insulating coating 2. The heat treatment pattern is basically the same as step S4a, except that differences in heat capacity of the articles to be heat treated are taken into consideration. Furthermore, from the perspective of controlling the spacing between the soft magnetic Fe-based alloy plates 1 and the thickness of the electrical insulating coating 2 in the laminated iron core, it is preferable to apply pressure in the stacking direction during heat treatment (particularly during the firing process).

[0061] If the soft magnetic Fe-based alloy plate shaping element step is not performed in step S1, an iron core shaping element step of shaping the laminated core into a desired shape may be performed as part of this process. There are no particular limitations on the shaping method for the laminated core, and conventional metal processing methods (e.g., laser processing, water jet processing, etc.) can be used as appropriate.

[0062] Step S5b is a step of forming a soft magnetic composite laminate by stacking a plurality of soft magnetic composite plates 10 prepared in step S4a. As in step S5a, there are no particular limitations on the method of stacking the soft magnetic composite plates 10, and conventional stacking methods for laminated iron cores can be used as appropriate.

[0063] Step S4c is a step of forming a laminated core by subjecting the soft magnetic composite laminate prepared in step S5b to heat treatment to soften, flow, and harden the electrical insulating coating 2 again, and joining the soft magnetic Fe-based alloy plates 1 together via the electrical insulating coating 2. The heat treatment pattern is basically the same as step S4b, but the drying process may be omitted.

[0064] Furthermore, if the soft magnetic Fe-based alloy plate shaping element step is not performed in step S1, an iron core shaping element step of shaping the laminated iron core into a desired shape may be performed as part of this process, similar to step S4b.

[0065] [Stator and rotating electrical machine using the soft magnetic composite material plate of the present invention] Fig. 6A is a schematic perspective view showing an example of a stator of a rotating electric machine, and Fig. 6B is an enlarged schematic cross-sectional view of a slot region of the stator. Note that the cross-sectional view refers to a cross section perpendicular to the direction of the rotation axis (a cross section whose normal is parallel to the axial direction). In a rotating electric machine, a rotor (not shown) is disposed radially inside the stator of Figs. 6A and 6B.

[0066] 6A and 6B, the stator 30 has stator coils 31 wound in multiple stator slots 21 formed on the inner periphery of the laminated core 20. The stator slots 21 are spaces that are arranged at a predetermined circumferential pitch around the circumferential direction of the laminated core 20 and penetrate the laminated core 20 in the axial direction, with slits 22 opening in the innermost periphery and extending in the axial direction. The areas separating adjacent stator slots 21 are called teeth 23 of the laminated core 20, and the parts of the inner periphery tip areas of the teeth 23 that define the slits 22 are called tooth claw portions 24.

[0067] The stator coil 31 is usually made up of a plurality of segment conductors 32. For example, in Figures 6A and 6B, the stator coil 31 is made up of three segment conductors 32 corresponding to the U-phase, V-phase, and W-phase of a three-phase AC. In order to prevent partial discharge between the segment conductors 32 and the laminated core 20 and between the phases (U-phase, V-phase, and W-phase), the outer periphery of each segment conductor 32 is usually covered with an electrical insulating material 33 (for example, insulating paper or enamel coating).

[0068] The rotating electric machine referred to here is a rotating electric machine that uses a laminated core 20 that employs the soft magnetic composite material plate 10 of the present invention. The laminated core 20 exhibits a lower Pi than laminated cores made of conventional electromagnetic steel sheets, conventional Fe-based amorphous alloy sheets, or conventional Fe-based nanocrystalline alloy sheets, and therefore can suitably accommodate higher rotation speeds and higher frequencies while suppressing energy loss and efficiency decline in the rotating electric machine. As a result, the rotating electric machine can achieve a higher output density than conventional machines. [Example]

[0069] The present invention will be explained in more detail below with reference to various experiments, however, the present invention is not limited to the configurations and structures described in these experiments.

[0070] [Experiment 1] (Soft magnetic Fe-based alloy plates SMP-1 and SMP-2 available) An Fe-based amorphous alloy plate (Magprost Co., Ltd., 1K101, thickness 25 μm) was prepared as the soft magnetic Fe-based alloy plate SMP-1, and an Fe-based nanocrystalline alloy plate (Magnet Institute Co., Ltd., NANOMET (registered trademark), NMAQ, thickness 25 μm) was prepared as the soft magnetic Fe-based alloy plate SMP-2. Note that NMAQ is an alloy plate that becomes an Fe-based nanocrystalline alloy plate by a specified nanocrystallization heat treatment.

[0071] (Property investigation of soft magnetic Fe-based alloy plates SMP-1 and SMP-2) The crystallization temperatures of the prepared SMP-1 and SMP-2 were measured using a differential thermal analyzer (Hitachi High-Tech Corporation, model: TG / DTA6200). The results are shown in Table 1 below. Figure 1 shown above is the DTA chart of SMP-1.

[0072] Based on the results of the DTA measurements, SMP-1 and SMP-2 were subjected to heat treatment to investigate the effect on Pi. The iron loss Pi of the samples was measured under the conditions of a magnetic flux density of 1.0 T, 400 Hz, and a temperature of 20°C using the H coil method (JIS C 2556:2015) using a BH loop analyzer (IFG Corporation, IF-BH550) and a vertical yoke single sheet tester. -1.0 / 400 The results are shown in Table 1.

[0073] [Table 1]

[0074] As shown in Table 1, both SMP-1 and SMP-2 exhibited sufficiently low Pi values for heat treatment at a temperature below the secondary crystallization temperature (505°C). -1.0 / 400 On the other hand, when heat treatment is performed at a temperature above the second crystallization temperature (700°C), Pi -1.0 / 400 is confirmed to increase dramatically.

[0075] [Experiment 2] (Preparation of lead-free glass compositions G-1 to G-3) Lead-free glass compositions G-1 to G-3 were prepared, each having the nominal composition shown in Table 2 below. The nominal compositions in the table are expressed as the mass ratio of each component converted to oxide. The starting materials used were V2O5 (Kojundo Chemical Laboratory Co., Ltd., purity 99.9%), P2O5 (Kojundo Chemical Laboratory Co., Ltd., purity 99.9%), BaCO3 (Kojundo Chemical Laboratory Co., Ltd., purity 99.9%), and Sb2O3 (Fujifilm Wako Pure Chemical Industries, Ltd., purity 99.9%). As can be seen from the purity of the starting materials, the lead-free glass composition used in the present invention contains a certain amount of unavoidable impurities.

[0076] The platinum crucible containing the mixed raw material powder was placed in a glass melting furnace and heated to 900°C at a heating rate of 5°C / min to melt the mixed raw material powder. The mixture was then held for 1 hour while stirring with an alumina rod to homogenize the composition of the melt in the platinum crucible. The platinum crucible was then removed from the glass melting furnace, and the melt was poured into a graphite mold preheated to 300°C to produce a bulk glass composition. The cast bulk was then transferred to a stress relief furnace preheated to a stress relief temperature, held for 1 hour to remove stress, and then cooled to room temperature at a rate of 1°C / min. The bulk cooled to room temperature was pulverized using a stamp mill and a jet mill to prepare powders of lead-free glass compositions G-1 to G-3.

[0077] (Measurement of characteristic temperatures of lead-free glass compositions G-1 to G-3) The characteristic temperatures of G-1 to G-3 were measured using the same differential thermal analyzer as in Experiment 1. The measurement conditions were as follows: α-alumina was used as the standard sample, the measurement atmosphere was nitrogen, and the heating rate was 5°C / min. The measurement results of the softening points Ts are also shown in Table 2.

[0078] [Table 2]

[0079] As shown in Table 2, it has been confirmed that lead-free glass compositions having desirable characteristic temperatures can be obtained by controlling the constituent components and contents of the glass. It has also been confirmed that the crystallization peak temperatures Tcp of G-1 to G-3 are each 45°C or more higher than Ts.

[0080] (Production of glass frits GF-1 to GF-9 and investigation of bulk properties) Glass frits GF-1 to GF-9, which serve as the base for the electrical insulating coating, were prepared by mixing the powders G-1 to G-3 prepared above with filler powder in the ratios shown in Table 3. As the filler powder, spherical SiO2 powder (average particle size 1 μm) was used.

[0081] Each of the prepared glass frits GF-1 to GF-9 was used to form a powder compact, which was then fired at a temperature 20°C higher than the Ts of the glass composition used to produce a bulk body corresponding to an electrical insulating coating. The bulk body was then ground into a prismatic shape (4 mm x 4 mm x 15 mm) to prepare a sample for measuring the linear expansion coefficient. The linear expansion coefficient of each sample was measured using a thermal dilatometer (ULVAC, Model DL-9600). The temperature range for measuring the linear expansion coefficient was from 30°C to a temperature below the Tg of the glass composition. The results are also shown in Table 3.

[0082] [Table 3]

[0083] As shown in Table 3, it is confirmed that the linear expansion coefficient of the electrical insulating film can be controlled by mixing a filler into the lead-free glass composition.

[0084] [Experiment 3] (Prepare glass paste GP-1 to GP-9) Glass pastes GP-1 to GP-9 for soft magnetic composite plates were prepared by mixing 100 parts by mass of each of the glass frits GF-1 to GF-9 prepared in Experiment 2 with 10 parts by mass of nitrocellulose as a resin binder and 20 parts by mass of α-terpineol as a solvent.

[0085] (Production of soft magnetic composite plates SMCM-1 to SMCM-28) Glass pastes GP-1 to GP-9 were applied to both main surfaces of the soft magnetic Fe-based alloy plates SMP-1 and SMP-2 prepared in Experiment 1 according to the specifications shown in Table 4 below to form soft magnetic composite material precursors. At this time, the thickness of the glass paste coating was controlled in order to control the electrical insulating film to the desired thickness.

[0086] Next, the soft magnetic composite material precursor was subjected to a drying process in which it was heated to 170°C and held there for 30 minutes, and then to a firing process in which it was heated to a temperature 20°C higher than the Ts of the glass composition used and held there for 30 minutes, to produce soft magnetic composite material plates SMCM-1 to SMCM-28.

[0087] (Property investigation of soft magnetic composite plates SMCM-1 to SMCM-28) For the fabricated SMCM-1 to SMCM-28, the iron loss Pi was measured in the same manner as in Experiment 1. -1.0 / 400 (Unit: W / kg) was measured. In Experiment 1, the Pi -1.0 / 400 The reduction rate (Pi reduction rate) was calculated from the above data. The results are shown in Table 4.

[0088] Pi -1.0 / 400 After the measurement, the sample was cut, and the Vickers hardness of the cross section of the soft magnetic Fe-based alloy plate was measured using a nanoindentation tester (Elionix Co., Ltd., model ENT-1100a), and the amount of strain in the soft magnetic Fe-based alloy plate was calculated. The results are also shown in Table 4.

[0089] [Table 4]

[0090] As shown in Table 4, SMCM-1 to SMCM-28 prepared according to the present invention all exhibited the same Pi content as SMP-1 alone and SMP-2 alone. -1.0 / 400 It is confirmed that the decrease is larger than that

[0091] (Investigation of breakdown of iron loss Pi and frequency dependency) The breakdown of iron loss Pi and its frequency dependence were investigated for the SMCM-21 and SMP-1 single bodies fabricated above. Regarding the breakdown of Pi, Pi was measured using the Steinmetz equation. -1.0 / 400 The results are shown in Table 5.

[0092] [Table 5]

[0093] As shown in Table 5, SMCM-21 has a significantly lower hysteresis loss than SMP-1 alone. This is thought to be due to the fact that electrical insulating coating 2 in SMCM-21 applies a tensile strain to SMP-1.

[0094] Regarding the frequency dependence of Pi, we measured Pi using the same equipment as in Experiment 1, but changing only the frequency conditions. -1.0 / 100 and iron loss at 200 Hz is Pi -1.0 / 200 and iron loss at 300 Hz is Pi -1.0 / 300 and iron loss at 500 Hz is Pi -1.0 / 500 The results are shown in Table 6.

[0095] [Table 6]

[0096] As shown in Table 6, Pi increases as the frequency increases. This shows that if the rotation speed and frequency during operation are increased in order to increase the output of electromechanical devices, energy loss and reduced efficiency due to Pi will become major problems.

[0097] In the case of SMCM-21 according to the present invention, Pi also increases as the frequency increases, but it has been confirmed that the degree of increase in Pi is more gradual than in the case of SMP-1 alone. In other words, it can be said that the soft magnetic composite plate according to the present invention can be effectively used in electromechanical devices that can handle higher rotation speeds and higher frequencies.

[0098] The above-described embodiments and experiments have been described to aid in understanding the present invention, and the present invention is not limited to the specific configurations described. For example, it is possible to replace part of the configuration of the embodiments with configurations within the technical common sense of those skilled in the art, and it is also possible to add configurations within the technical common sense of those skilled in the art to the configuration of the embodiments. In other words, it is possible to delete, replace, or add part of the configurations of the embodiments and experiments in this specification without departing from the technical spirit of the invention. [Explanation of symbols]

[0099] 1...soft magnetic Fe-based alloy plate, 2...electrical insulating coating, 10...soft magnetic composite material plate, 20...laminated core, 21... stator slot, 22... slit, 23... teeth, 24... teeth claw portion, 30...stator, 31...stator coil, 32...segment conductor, 33...electrical insulating material.

Claims

1. A soft magnetic composite plate having a soft magnetic Fe-based alloy plate and an electrically insulating coating formed on the surface of the soft magnetic Fe-based alloy plate, the soft magnetic Fe-based alloy plate is an Fe-based amorphous alloy plate or an Fe-based nanocrystalline alloy plate; the electrical insulating coating contains a lead-free glass composition and has a linear expansion coefficient less than that of the soft magnetic Fe-based alloy plate, The glass composition has a softening point equal to or lower than a temperature at which the microstructure of the soft magnetic Fe-based alloy plate is maintained. A soft magnetic composite plate characterized by:

2. 2. The soft magnetic composite plate according to claim 1, The glass composition has the following nominal components expressed as oxides: 40% to 70% by mass of V 2 O 5 and 10% by mass or more and 35% by mass or less of P 2 O 5 and V 2 O 5 and the aforementioned P 2 O 5 and the total of these is 50% by mass or more and 98% by mass or less, BaO, Sb 2 O 3 , WO 3 , ZnO, K 2 O, Fe 2 O 3 , TeO 2 , Ag 2 O, and Li 2 O in a total amount of 2% by mass or more and 50% by mass or less, The remainder is unavoidable impurities. A soft magnetic composite plate characterized by:

3. 3. The soft magnetic composite plate according to claim 2, the electrical insulating coating contains 75% by volume or less of a filler of oxide particles; The filler is SiO 2 , ZrO 2 , Al 2 O 3 , Nb 2 O 5 , ZrSiO 4 , Zr 2 (WO 4 )(PO 4 ) 2 , 2MgO·2Al 2 O 3 ・5SiO 2 , 3Al 2 O 3 ・2SiO 2 , and LiAlSiO 4 one or more of the group consisting of A soft magnetic composite plate characterized by:

4. 4. The soft magnetic composite plate according to claim 3, the linear expansion coefficient of the electrical insulating coating is less than 10 ppm / °C; The softening point of the glass composition is 500°C or less. A soft magnetic composite plate characterized by:

5. The soft magnetic composite plate according to any one of claims 1 to 4, The soft magnetic Fe-based alloy plate has a tensile strain in the in-plane direction within a range of 1 μST to 1000 μST.

6. A method for manufacturing a soft magnetic composite plate according to any one of claims 1 to 4, a soft magnetic Fe-based alloy plate preparation step of preparing a soft magnetic Fe-based alloy plate; a glass paste preparation step of preparing a glass paste that is a base for the electrical insulating coating; a soft magnetic composite material precursor forming step of forming a soft magnetic composite material precursor by applying the glass paste to at least one main surface of the soft magnetic Fe-based alloy plate; an electrical insulating film forming step of forming the electrical insulating film by heat treating the soft magnetic composite material precursor; A method for manufacturing a soft magnetic composite plate, comprising:

7. 7. The method for manufacturing a soft magnetic composite plate according to claim 6, The heat treatment in the electrical insulating coating forming step includes a drying process of heating to and maintaining a temperature of 120°C or higher and 200°C or lower, and a firing process of heating to and maintaining a temperature that is 20°C to 50°C higher than the softening point of the glass composition, the maximum temperature of the firing process is lower than the crystallization peak temperature of the glass composition and lower than the second crystallization temperature of the soft magnetic Fe-based alloy plate; A method for manufacturing a soft magnetic composite material plate.

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