A method for simultaneously reducing hysteresis loss and eddy current loss of FeSiAl magnetic powder core

Abstract

The present invention discloses a method for synchronously reducing the hysteresis loss and eddy current loss of FeSiAl magnetic powder cores, which comprises the following steps: preparing a salt solution of metal M, wherein the metal M is a low-melting-point metal with an atomic radius unequal to that of Al atoms and can form a substitutional solid solution with Al; adding the salt solution to the FeSiAl magnetic powder core, drying to obtain a magnetic powder core with good insulation coating, and then adding a binder and a lubricant to make a magnetic powder to be formed; pressing the magnetic powder to be formed into shape, and obtaining a magnetic powder core after heat treatment. In the present invention, low-melting-point M atoms diffuse into the FeSiAl matrix and occupy Al vacancies, which can reduce lattice distortion during the annealing process, thereby reducing the coercivity and hysteresis loss; more importantly, after M atoms are incorporated into FeSiAl, the resistivity of the matrix increases, which can effectively inhibit the eddy current loss in the particles. At the same time, the in-situ oxidized Al2O3 coating layer can effectively isolate the eddy current loss between particles. Therefore, the method of the present invention realizes the synchronous reduction of hysteresis loss and eddy current loss.

Description

Technical Field

[0001] The invention belongs to the technical field of metal magnetic powder core materials, and in particular relates to a method for synchronously reducing hysteresis loss and eddy current loss of a FeSiAl magnetic powder core. Background Art

[0002] Among many soft magnetic materials, FeSiAl soft magnetic composite materials (magnetic powder cores) prepared by processes such as insulation coating, compression molding and annealing heat treatment combine the advantages of soft magnetic alloys and ferrites, have relatively high resistivity and saturation magnetization, and are widely used as components or devices for storing, transmitting and converting electromagnetic energy and information, and have broad application scenarios. With the rapid development of emerging industries such as new energy vehicles, photovoltaics, and 5G communications, the operating frequency and power of devices have increased, and the power loss of magnetic powder cores has increased rapidly, resulting in an irreversible decrease in magnetic properties. Therefore, it is urgent to develop high-frequency, high-performance FeSiAl magnetic powder cores to realize the development of electrical and electronic devices towards high frequency and high power.

[0003] In the design and preparation of magnetic materials, it is necessary to reduce the core loss (P cv ) is very important. Core loss refers to the energy loss generated by magnetic materials during AC magnetization, mainly including hysteresis loss (P h )、eddy current loss(P e ) and residual loss (P c ) three parts. Hysteresis loss is proportional to the first power of frequency, while eddy current loss is proportional to the square of frequency. Therefore, at high frequency MHz, the loss of the magnetic core increases sharply. If the core loss is too large, it will affect the service life of the core and may affect the normal operation of the product using the core. Therefore, people are constantly looking for ways to reduce the loss of the core at high frequency MHz to improve the efficiency of magnetic components, reduce temperature rise, and enhance reliability.

[0004] Eddy current loss includes eddy current loss between particles and eddy current loss within particles. The eddy current loss between particles can be curbed by an insulating coating process, but few people have achieved the reduction of eddy current loss within particles in the prior art. For example, one of the prior arts is to reduce the eddy current loss between particles by doping elements in the original ingot, inducing grain refinement, and thus reducing the particle size; that is, pouring various molten metal alloys into a mold for cooling and solidification, and introducing metal elements for doping during this process. Although this method can reduce eddy current loss by reducing particle size, its essence is mainly to reduce eddy current loss between particles through later insulating coating, but element doping cannot be precisely controlled during alloy smelting. Moreover, after alloy smelting, due to the reduction of grain size, the increase of grain boundaries, and the enhanced pinning effect at the grain boundaries, the hysteresis loss will be worsened. In addition, the above method has basically no effect on reducing eddy current loss within particles. In addition, the inventor team proposed Chinese patent CN202210079110.6 earlier, which discloses a confined insulation coated soft magnetic silicon aluminum process and its products. Instead of using the original ingot casting method, the segregated Al atoms and oxygen storage materials undergo confined solid phase reaction to obtain a dense Al2O3 insulating layer to reduce the eddy current loss between particles. However, the above process cannot reduce the increase in hysteresis loss caused by lattice deformation caused by Al vacancies, nor can it increase the resistivity of the FeSiAl matrix. Therefore, it still does not achieve the reduction of eddy current loss within the particles and the reduction of hysteresis loss. In addition, a similar principle is also disclosed in Chinese patent CN202310004560.3, which is to generate an Al2O3 layer in situ by aluminothermic reaction between segregated Al atoms and metal oxides to isolate the eddy current loss between particles; however, this method only electrically isolates different particles, and has similar defects to Chinese patent CN202210079110.6. Therefore, it can be found that it is difficult to simultaneously reduce hysteresis loss and eddy current loss at high frequencies MHz.

[0005] In summary, how to significantly reduce the eddy current loss within the particles while also significantly reducing the hysteresis loss (especially at high frequencies of MHz) is a problem that still needs to be solved in this field. Summary of the invention

[0006] One object of the present invention is to overcome the shortcomings of the prior art and provide a method for simultaneously reducing the hysteresis loss and eddy current loss of a magnetic powder core, thereby ultimately obtaining a high-frequency, high-performance FeSiAl magnetic powder core. The magnetic powder core prepared by the method has ultra-low loss, can solve the problem of high loss of the magnetic powder core at high frequency, and has low cost, simple operation, and is easy to mass produce.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for simultaneously reducing hysteresis loss and eddy current loss of a FeSiAl magnetic powder core comprises the following steps:

[0009] Step (1): Insulation coating

[0010] 1.1 Dissolve 0.05 to 3 parts by weight of a metal M salt in a solvent to prepare a metal M salt solution, wherein the metal M is a low melting point metal and can form a substitutional solid solution with Al;

[0011] Specifically, the melting point of the metal M is lower than 700° C., its atomic radius is not equal to that of the Al atom, and it can form a substitutional solid solution with Al on the phase diagram, and Al can replace M in the metal M salt;

[0012] 1.2 Add the salt solution of metal M to 100 parts by weight of FeSiAl magnetic powder core, dry it at 60-80°C to obtain an insulating coated magnetic powder core;

[0013] 1.3 Dissolve 0.5-2 parts by weight of a binder in 1.5-6 parts by weight of an organic solvent and add it to the above-mentioned insulated coated magnetic powder core, stir thoroughly and dry at 60-80°C;

[0014] 1.4 After the magnetic powder core is cooled, add 0.5 to 1.5 parts by weight of lubricant and stir thoroughly to form the magnetic powder to be formed.

[0015] Preferably, the metal M is Sn (tin), Bi (bismuth) or In (indium).

[0016] Preferably, the specific preparation process of step 1.1 is to mix 1 to 20 parts by weight of a solvent and 0.05 to 3 parts by weight of a metal M salt to obtain a colorless transparent solution; the metal M salt can be one or more of SnCl4, SnCl2, Sn(NO3)4, BiCl3, Bi(NO3)3, InCl3, In (NO3)3; the solvent is a good solvent for the metal M salt, such as water or an alcohol solvent, more preferably anhydrous ethanol.

[0017] Preferably, the adhesive is one or more of epoxy resin, silicone resin, silicon dioxide, glass powder, and water glass.

[0018] Preferably, the organic solvent is acetone.

[0019] Preferably, the lubricant is one or two of zinc stearate, aluminum stearate and barium stearate.

[0020] Step (2): Compression molding

[0021] The magnetic powder to be formed is formed into a green body at a pressure of 1200-2200 MPa.

[0022] Step (3): Heat treatment

[0023] The green body is heat treated in an inert atmosphere, and finally cooled and sprayed to obtain a magnetic powder core; wherein the annealing temperature is 500-800°C, and the annealing time is 0.5-3h.

[0024] Preferably, the inert atmosphere is nitrogen or argon.

[0025] Another object of the present invention is to provide a low-loss FeSiAl magnetic powder core prepared by the above method.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] The present invention directly uses metal salts of low-melting-point atoms M to replace metal oxides of oxygen storage materials in the process of making FeSiAl:M / Al2O3 blanks. In addition to being able to achieve in-situ Al2O3 coating layer and reduce inter-particle eddy current loss, the present invention can also achieve M atoms diffusing into the FeSiAl matrix and occupying Al vacancies during annealing, which can reduce lattice distortion, thereby greatly reducing coercive force and hysteresis loss, especially at high frequencies MHz; and after M atoms occupy Al vacancies, they can enhance the electron-phonon scattering of the FeSiAl matrix and significantly suppress the intra-particle eddy current loss. At the same time, the Al2O3 coating layer formed by this method can effectively isolate the inter-particle eddy current loss, thereby reducing the loss in all directions.

[0028] In summary, the present invention achieves a significant reduction in the hysteresis loss, inter-particle eddy current loss and intra-particle eddy current loss of the magnetic powder core at high frequency MHz by replacing metal oxides with low-melting-point metal M salts. This method has a simple process flow, low cost, no pollution to the environment, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the present invention.

[0030] Figure 2 The transmission electron microscope (a) and energy spectrum (b) of the FeSiAl:Sn / Al2O3 magnetic powder core prepared by the present invention confirm the structure of the FeSiAl:Sn / Al2O3 magnetic powder core;

[0031] Figure 3 (a) is the X-ray diffraction pattern of FeSiAl particles and different FeSiAl particles after annealing at 700℃ for 1h, (b) is the enlarged image of the (220) diffraction crystal plane;

[0032] Figure 4The piezoelectric force microscope images of the uncoated (ac) and coated (df) magnetic powder cores show that after coating, the current of the FeSiAl:Sn matrix decreases and the resistivity increases because Sn atoms occupy the positions of Al atoms. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the technical scheme provided by the present application and the given embodiments, all other technical schemes obtained by those skilled in the art without making creative work, all belong to the scope of protection of the present application. Those who do not specify specific conditions in the embodiment shall proceed according to normal conditions or conditions recommended by the manufacturer. Those who do not specify the manufacturer for reagents or instruments used in the present application are all conventional products that can be purchased commercially.

[0034] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range or the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges.

[0035] As mentioned above, in view of the shortcomings of the prior art, the inventors of this case proposed the technical solution of the present invention after long-term research and extensive practice, which is mainly based on at least: on the one hand, combined with the rapid thermal diffusion of Al atoms during the annealing process, the Al atoms in the aluminum-rich layer can replace the metal M in the M salt, and in situ oxidize themselves on the surface of the magnetic powder core to generate Al2O3 with high resistivity, which can suppress the eddy current loss between particles; on the other hand, the low-melting-point M metal atoms can diffuse into the FeSiAl matrix and occupy Al vacancies, thereby reducing lattice distortion and reducing coercive force and hysteresis loss. More importantly, after M atoms occupy Al vacancies, they can increase the resistivity of the matrix, thereby suppressing the eddy current loss in the particles. Through the above method, the power loss of the magnetic powder core at high frequency MHz can be effectively reduced.

[0036] like Figure 1As shown, it is a schematic diagram of the present invention. In the method of the present invention, the segregated Al atoms replace the metal M in the M salt, and at the same time, they undergo an oxidation reaction to form an Al2O3 insulating layer, thereby reducing the eddy current loss between particles. More importantly, the low-melting-point M atoms can enter the FeSiAl matrix, occupy the Al vacancies, and reduce the hysteresis loss caused by the lattice deformation caused by the Al vacancies. At the same time, the Sn atom doping can increase the resistivity of the FeSiAl matrix, thereby suppressing the eddy current loss within the particles. Therefore, the method of the present invention can achieve the purpose of reducing the loss of the magnetic powder core at high frequencies.

[0037] Specifically, the present invention provides a method for simultaneously reducing the hysteresis loss and eddy current loss of a FeSiAl magnetic powder core, comprising the following steps:

[0038] Step (1): Insulation coating

[0039] 1.1 0.05-3 parts by weight of a metal M salt and 1-15 parts by weight of anhydrous ethanol are mixed to prepare a salt solution of metal M, wherein the metal M is a low melting point metal that can form a substitutional solid solution with Al on a phase diagram, and its atomic radius is not equal to that of an Al atom (close to that of an Al atom);

[0040] 1.2 Add the above salt solution to 100 parts by weight of FeSiAl magnetic powder core, dry it at 60-80°C to obtain an insulating coated magnetic powder core;

[0041] 1.3 Dissolve 0.5-2 parts by weight of a binder in 1.5-6 parts by weight of an organic solvent and add the mixture to the above-mentioned insulated and coated magnetic powder core. Stir thoroughly and dry at 60-80°C.

[0042] 1.4 After the magnetic powder core is cooled, add 0.5 to 1.5 parts by weight of lubricant and stir thoroughly to form the magnetic powder to be formed.

[0043] Step (2): Compression molding

[0044] The magnetic powder to be formed is formed into a green body at a pressure of 1200-2200 MPa.

[0045] Step (3): Heat treatment

[0046] The green body is heat treated in an inert atmosphere, and finally cooled and sprayed to obtain a magnetic powder core; wherein the annealing temperature is 500-800°C, and the annealing time is 0.5-3h.

[0047] Preferably, the inert atmosphere is nitrogen or argon.

[0048] In some embodiments, the atomic radius of the metal M is slightly larger or smaller than that of the Al atom, and Al can replace M in the metal M salt, specifically Sn (tin), Bi (bismuth), In (indium) or other metals that meet the above conditions.

[0049] In some embodiments, the metal M salt may be one or more of SnCl4, SnCl2, Sn(NO3)4, BiCl3, Bi(NO3)3, InCl3, In (NO3)3.

[0050] In some embodiments, the weight proportion of the metal M salt is 0.05 to 3 parts, specifically selected from 0.1 parts, 0.3 parts, 0.5 parts, 0.7 parts, 0.9 parts, 1.1 parts, 1.3 parts, 1.5 parts, 1.7 parts, 1.9 parts, 2.1 parts, 2.3 parts, 2.5 parts, 2.7 parts, 2.9 parts, 3 parts, or other values ​​within the range, which can be selected according to actual needs and is not limited here.

[0051] In some embodiments, the weight proportion of anhydrous ethanol is 1 to 15 parts, specifically selected from 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, or other values ​​within the range, which can be selected according to actual needs and is not limited here.

[0052] In some embodiments, the binder is one or more of epoxy resin, silicone resin, silica, glass powder, and water glass; the weight proportion of the binder is 0.5 to 2 parts, specifically 0.5 parts, 1 part, 1.5 parts, 2 parts, or other values ​​within the range, which can be selected according to actual needs and is not limited here.

[0053] In some embodiments, the organic solvent is acetone; the weight proportion of the organic solvent is 1.5 to 6 parts, specifically 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, or other values ​​within the range, which can be selected according to actual needs and is not limited here.

[0054] In some embodiments, the lubricant is one or two of zinc stearate, aluminum stearate, and barium stearate; the weight proportion of the lubricant is 0.5 to 1.5 parts, specifically 0.5 parts, 0.7 parts, 0.9 parts, 1.1 parts, 1.3 parts, 1.5 parts, or other values ​​within the range, which can be selected according to actual needs and is not limited here.

[0055] In some embodiments, the pressure of compression molding is 1200~2200 MPa, and can be specifically selected from 1200MPa, 1400MPa, 1600MPa, 1800MPa, 2000MPa, 2200MPa, or other values ​​within the range, which can be selected according to actual needs and is not limited here.

[0056] In some embodiments, the annealing temperature is 500-800°C, specifically selected from 500°C, 520°C, 540°C, 560°C, 580°C, 600°C, 620°C, 640°C, 660°C, 680°C, 700°C, 720°C, 740°C, 760°C, 780°C, 800°C; the annealing time is 0.5-3h, specifically selected from 0.5h, 1h, 1.5h, 2h, 2.5h, 3h; it can also be other values ​​within the above range, which can be selected according to actual needs and is not limited here.

[0057] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0058] The soft magnetic metal powder used in the following examples is the soft magnetic metal powder prepared by the gas atomization method.

[0059] Embodiment 1:

[0060] (1) Dissolve 2 g of SnCl4 in 15 g of anhydrous ethanol, stir in a sealed container for 3 h, and then leave at room temperature for 24 h to obtain a uniform and transparent metal salt solution.

[0061] (2) Mix 100 g of FeSiAl soft magnetic powder into the above solution, heat it to 60°C and dry it to obtain an insulating coated magnetic powder core.

[0062] (3) Dissolve 1 g of epoxy resin in 3 g of acetone to obtain an epoxy resin solution, and heat the solution to 60°C and dry it.

[0063] (4) Add 0.5 g of zinc stearate to the magnetic powder core treated in step (3) and mix them evenly to obtain magnetic powder to be formed.

[0064] (5) The magnetic powder to be formed after insulation coating is formed into a green body at a pressure of 1800 MPa, with an outer diameter of 12.7 mm, an inner diameter of 7.60 mm, and a height of 5.2 mm.

[0065] (6) The green body is heat treated in vacuum at an annealing temperature of 720°C for 1 hour, cooled, and sprayed to obtain a magnetic powder core. The transmission electron microscopy and energy spectrum of the magnetic powder core are shown in FIG. Figure 2 As shown by Figure 2 It can be seen that there is a uniform Al2O3 insulating layer between FeSiAl particles, which can effectively suppress the eddy current loss between particles.

[0066] X-ray diffraction analysis (XRD) was performed on the original FeSiAl particles, the FeSiAl particles after annealing, and the Sn-doped FeSiAl particles after annealing. The results are as follows: Figure 3 As shown. Figure 3 It can be seen that after annealing, the interplanar spacing decreases and the diffraction peak shifts to a higher angle because Al atoms are easily segregated to the surface and oxidized. After a certain amount of Sn is added to the FeSiAl matrix, the interplanar spacing increases, the lattice deformation decreases, and the diffraction peak shifts back, which means that FeSiAl:M can reduce lattice deformation, coercivity and hysteresis loss.

[0067] Embodiment 2:

[0068] (1) Dissolve 1 g of SnCl2 in 10 g of anhydrous ethanol, stir in a sealed container for 3 h, and then leave at room temperature for 24 h to obtain a uniform and transparent metal salt solution.

[0069] (2) Mix 100 g of FeSiAl soft magnetic powder into the above salt solution, heat it to 60°C and dry it to obtain an insulating coated magnetic powder core.

[0070] (3) Dissolve 1 g of epoxy resin in 3 g of acetone to obtain an epoxy resin solution, and heat the solution to 60°C and dry it.

[0071] (4) Add 0.5 g of zinc stearate to the magnetic powder core treated in step (3) and mix them evenly to obtain magnetic powder to be formed.

[0072] (5) The magnetic powder to be formed after insulation coating is formed into a green body at a pressure of 1800 MPa, with an outer diameter of 12.7 mm, an inner diameter of 7.60 mm, and a height of 5.2 mm.

[0073] (6) The blank is heat treated in vacuum at an annealing temperature of 700°C for 1 h, cooled, and sprayed to obtain a magnetic powder core.

[0074] Embodiment 3:

[0075] (1) Dissolve 0.6 g of InCl3 in 8 g of anhydrous ethanol, stir in a sealed container for 3 h, and then leave at room temperature for 24 h to obtain a uniform and transparent metal salt solution.

[0076] (2) Mix 100 g of FeSiAl soft magnetic powder into the above salt solution, heat it to 60°C and dry it to obtain an insulating coated magnetic powder core.

[0077] (3) Dissolve 1 g of epoxy resin in 3 g of acetone to obtain an epoxy resin solution, and heat the solution to 60°C and dry it.

[0078] (4) Add 0.5 g of zinc stearate to the magnetic powder core treated in step (3) and mix them evenly to obtain magnetic powder to be formed.

[0079] (5) The magnetic powder to be formed after insulation coating is formed into a green body at a pressure of 1800 MPa, with an outer diameter of 12.7 mm, an inner diameter of 7.60 mm, and a height of 5.2 mm.

[0080] (6) The blank is heat treated in vacuum at an annealing temperature of 700°C for 1 h, cooled, and sprayed to obtain a magnetic powder core.

[0081] Embodiment 4:

[0082] (1) Dissolve 0.08 g of BiCl3 in 6 g of anhydrous ethanol, stir in a sealed container for 3 h, and then leave at room temperature for 24 h to obtain a uniform and transparent metal salt solution.

[0083] (2) Mix 100 g of FeSiAl soft magnetic powder into the above salt solution, heat it to 60°C and dry it to obtain an insulating coated magnetic powder core.

[0084] (3) Dissolve 1 g of epoxy resin in 3 g of acetone to obtain an epoxy resin solution, and heat the solution to 60°C and dry it.

[0085] (4) Add 0.5 g of zinc stearate to the magnetic powder core treated in step (3) and mix them evenly to obtain magnetic powder to be formed.

[0086] (5) The magnetic powder to be formed after insulation coating is formed into a green body at a pressure of 1800 MPa, with an outer diameter of 12.7 mm, an inner diameter of 7.60 mm, and a height of 5.2 mm.

[0087] (6) The blank is heat treated in vacuum at an annealing temperature of 700°C for 1 h, cooled, and sprayed to obtain a magnetic powder core.

[0088] Test Example 1

[0089] The performance test and loss separation results of the magnetic powder cores prepared in Examples 1 to 4 are shown in Table 1 below:

[0090] Table 1 Magnetic powder core performance test results

[0091]

[0092] It can be seen from Table 1 that the eddy current loss and hysteresis loss of the magnetic powder core prepared by the method of the present invention are greatly reduced at high frequency MHz; this is because in the preparation process of the present invention, the M atoms (i.e. Sn, Bi, In) in the M salt diffuse into the FeSiAl matrix and occupy Al vacancies, which can reduce lattice distortion, thereby greatly reducing coercive force and hysteresis loss; in addition, after the M atoms occupy the Al vacancies, the electron-phonon scattering of the FeSiAl matrix is ​​enhanced to suppress the eddy current loss within the particles, and the Al atoms themselves undergo an oxidation reaction to obtain an Al2O3 coating layer in situ to reduce the eddy current loss between particles, thereby comprehensively achieving all-round loss reduction.

[0093] The uncoated and coated FeSiAl magnetic powder cores were observed under a piezoelectric force microscope. The results are shown in Figure 4 As shown; after coating, since Sn atoms occupy the position of Al atoms, the current of the FeSiAl:Sn matrix decreases, the resistivity increases, and the eddy current loss in the particles decreases, further confirming the mechanism of the present invention for reducing the eddy current loss in the particles.

[0094] Therefore, the magnetic powder core obtained by the confined coating process of the present invention has low loss at high frequency. The method of the present invention can achieve the simultaneous reduction of inter-particle eddy current loss, intra-particle eddy current loss and hysteresis loss of the magnetic powder core at high frequency MHz, and the method is easy to mass produce and has good application prospects.

[0095] The above embodiments are not limitations of the present invention, and the present invention is not limited to the above embodiments. As long as they meet the requirements of the present invention, they belong to the protection scope of the present invention. The above implementation modes are only used to illustrate the present application and are not limited to the technical solutions described in the present application. The understanding of the present application should be based on the technical personnel in the relevant technical field. Although the present application has been described in detail with reference to the above implementation modes, the ordinary technicians in the field should understand that the technical personnel in the relevant technical field can still modify or replace the present application with equivalents, and all technical solutions and improvements that do not depart from the spirit and scope of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for simultaneously reducing hysteresis loss and eddy current loss of FeSiAl magnetic powder core, comprising the following steps: Step (1), insulation coating: Insulating and coating the magnetic powder core to obtain magnetic powder to be formed; Step (2), compression molding: Pressing the magnetic powder to be formed obtained in step (1) into a green body; Step (3), heat treatment: The green body obtained in step (2) is heat treated in an inert atmosphere, and finally cooled and sprayed to obtain a FeSiAl:M / Al2O3 magnetic powder core; The method is characterized in that step (1) specifically comprises: 1.1 Dissolve 0.05 to 3 parts by weight of a metal M salt in a solvent to prepare a metal M salt solution; the metal M is a low melting point metal whose atomic radius is not equal to that of Al atoms and can form a substitutional solid solution with Al, specifically Sn, Bi or In; 1.2 Add the salt solution of metal M to 100 parts by weight of FeSiAl magnetic powder core, and dry to obtain an insulating coated magnetic powder core; 1.3 Dissolve 0.5-2 parts by weight of a binder in 1.5-6 parts by weight of an organic solvent and add the mixture to the insulating coated magnetic powder core, stir thoroughly and dry. 1.4 After the magnetic powder core is cooled, add 0.5 to 1.5 parts by weight of lubricant and stir thoroughly to form the magnetic powder to be formed.

2. The method according to claim 1, characterized in that The metal M salt in step 1.1 is one or more of SnCl4, SnCl2, Sn(NO3)4, BiCl3, Bi(NO3)3, InCl3, and In (NO3)3.

3. The method according to claim 1, characterized in that The adhesive in step 1.2 is one or more of epoxy resin, silicone resin, silicon dioxide, glass powder, and water glass.

4. The method according to claim 1, characterized in that: The drying temperature in step 1.2 and step 1.3 is 60~80℃.

5. The method according to claim 1, characterized in that The organic solvent in step 1.3 is acetone.

6. The method according to claim 1, characterized in that The lubricant in step 1.4 is one or two of zinc stearate, aluminum stearate, and barium stearate.

7. The method according to claim 1, characterized in that The pressure of the pressing molding in step (2) is 1200~2200MPa.

8. The method according to claim 1, characterized in that The heat treatment in step (3) adopts an annealing process; the annealing temperature is 500~800℃, and the annealing time is 0.5~3h.

9. A low-loss FeSiAl:M / Al2O3 magnetic powder core prepared by the method according to any one of claims 1 to 8.

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