An organic-inorganic composite-coated iron-based soft magnetic composite material and preparation method thereof

Abstract

The present invention belongs to the technical field of soft magnetic composite materials, and relates to an iron-based soft magnetic composite material with an organic-inorganic composite coating and a preparation method thereof. Modified alumina is obtained by modifying nano-alumina with a silane coupling agent; reduced iron powder, modified alumina, epoxy-modified silicone resin and an organic solvent are mixed evenly, and the organic solvent is removed to obtain a soft magnetic metal powder material with a surface coating; the soft magnetic metal powder material with a surface coating is mixed with a lubricant and then pressed into a shape, and then heat-treated at 300-500 °C to obtain the product; wherein, the mass ratio of the reduced iron powder, the modified alumina, and the epoxy-modified silicone resin is 100:0.2-0.6:1.4-1.8. The present invention can enable the soft magnetic composite material to maintain good magnetic properties on the basis of reducing magnetic loss.

Description

Technical Field

[0001] The invention belongs to the technical field of soft magnetic composite materials and relates to an organic-inorganic composite-coated iron-based soft magnetic composite material and a preparation method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Soft magnetic composite materials refer to composite materials with a core-shell structure, made by insulating and coating ferromagnetic particles and then forming them through powder metallurgy compression molding. With the rapid development of modern computer technology, the power electronics industry, and the defense and military industries, traditional soft magnetic materials such as silicon steel sheets and soft ferrites can no longer meet the requirements of miniaturization and high precision. It is imperative to develop new soft magnetic materials with excellent overall properties, such as low loss, high magnetic permeability, and high saturation magnetic induction intensity. Iron-based soft magnetic composites, made from iron powder, are low-cost, have high saturation magnetic flux density and permeability, and their excellent plasticity facilitates molding. They are being extensively researched and applied in fields such as electric motors and filters.

[0004] Insulation coating is the core technology for the preparation of soft magnetic composite materials. Its primary purpose is to increase the overall resistivity and thus reduce eddy current losses by coating magnetic powder with insulating materials. Different molding methods all utilize the high molding freedom of powder to form complex shapes to adapt to specific applications, and are also selected and studied according to actual conditions. On this basis, both inorganic insulation coating and organic insulation coating have been tried as insulating coating layers to obtain excellent soft magnetic properties. Some organic materials such as epoxy resin, phenolic resin and polypropylene have shown good bonding and coating properties, but the inventors have found that it is difficult for soft magnetic composite materials to maintain good magnetic properties while reducing magnetic losses. Summary of the Invention

[0005] In order to address the deficiencies of the prior art, the present invention aims to provide an organic-inorganic composite coated iron-based soft magnetic composite material and a preparation method thereof, which can enable the soft magnetic composite material to maintain good magnetic properties while reducing magnetic loss.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] On the one hand, a preparation method of an organic-inorganic composite-coated iron-based soft magnetic composite material, which modifies nano-aluminum oxide with a silane coupling agent to obtain modified aluminum oxide; mixes reduced iron powder, modified aluminum oxide, epoxy-modified silicone resin and an organic solvent evenly, and obtains a surface-coated soft magnetic metal powder material after removing the organic solvent; mixes the surface-coated soft magnetic metal powder material with a lubricant and presses it into a mold, and then heats it to 300-500 °C for heat treatment to obtain the product;

[0008] Among them, the mass ratio of the reduced iron powder, the modified aluminum oxide, and the epoxy-modified silicone resin is 100:0.2-0.6:1.4-1.8.

[0009] On the other hand, an organic-inorganic composite-coated iron-based soft magnetic composite material is obtained by the above preparation method.

[0010] In the third aspect, an application of the above-mentioned organic-inorganic composite-coated iron-based soft magnetic composite material in a motor or a filter.

[0011] The beneficial effects of the present invention are as follows:

[0012] The present invention uses nano-aluminum oxide and epoxy-modified silicone resin for organic-inorganic insulation coating. Because the surface of nano-aluminum oxide is rich in hydroxyl groups, it can better bond with the epoxy groups in the epoxy-modified silicone resin through the silane coupling agent, so that the nano-aluminum oxide in the prepared coating layer can be more evenly dispersed in the silicone resin to form a uniform coating layer.

[0013] The present invention obtains a metal soft magnetic powder core with low loss by mixing the surface-coated soft magnetic metal powder material with a lubricant and pressing it into a mold and then performing heat treatment. Moreover, the organic-inorganic composite-coated iron-based soft magnetic composite material prepared by the present invention has the characteristics of high frequency, high power and low loss.

[0014] The preparation method of the present invention has low requirements for equipment and low cost, and can basically meet the requirements of industrial production. Description of the Drawings

[0015] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0016] Figure 1 It is a process flow chart for coating reduced iron powder in an embodiment of the present invention;

[0017] Figure 2 It is a Mapping image of the reduced iron powder after organic-inorganic composite coating prepared in Example 1 of the present invention;

[0018] Figure 3Curve of the loss of the reduced iron powder after organic-inorganic composite coating prepared in the embodiments of the present invention. Detailed implementation manners

[0019] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further descriptions of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0020] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary implementation manners according to the present invention. As used herein, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0021] In view of the problem that it is difficult for current soft magnetic composite materials to simultaneously reduce magnetic loss and maintain magnetic properties, the present invention proposes an organic-inorganic composite-coated iron-based soft magnetic composite material and a preparation method thereof.

[0022] In a typical implementation manner of the present invention, a preparation method of an organic-inorganic composite-coated iron-based soft magnetic composite material is provided. Modified alumina is obtained by modifying nano-alumina with a silane coupling agent; an iron-based powder, the modified alumina, an epoxy-modified silicone resin and an organic solvent are mixed evenly, and after removing the organic solvent, a surface-coated soft magnetic metal powder material is obtained; the surface-coated soft magnetic metal powder material is mixed with a lubricant and then pressed into a mold, and then heat-treated at 300-500 °C to obtain the product.

[0023] Wherein, the mass ratio of the iron-based powder, the modified alumina, and the epoxy-modified silicone resin is 100:0.2-0.6:1.4-1.8.

[0024] In some embodiments, the modified alumina is 9-11% of the total mass of the modified alumina and the epoxy-modified silicone resin. Research shows that under this condition, not only can the magnetic loss be reduced, but also the saturation magnetization intensity can be improved.

[0025] In some embodiments, the silane coupling agent is hydrolyzed, and then the hydrolyzed silane coupling agent is coupled with nano-alumina to obtain modified alumina.

[0026] Specifically, the process of obtaining modified alumina by modifying nano-alumina with a silane coupling agent is as follows: the silane coupling agent is hydrolyzed to obtain a hydrolysis solution, the hydrolysis solution is mixed with a nano-alumina dispersion, and the mixture is heated to 70-90 °C for reaction, and then centrifuged to obtain the modified alumina.

[0027] More specifically, a silane coupling agent is added to water, and the pH is adjusted to 3-4 to obtain a hydrolysis solution. Preferably, acetic acid is used to adjust the pH.

[0028] More specifically, nano-aluminum oxide is mixed uniformly with ethanol and water, and ultrasonic treatment is carried out to obtain a nano-aluminum oxide dispersion. The mass-volume ratio of nano-aluminum oxide to the liquid is 2.0-3.0:100, g:mL.

[0029] More specifically, the heating reaction time is 3-5 h.

[0030] In some embodiments, the silane coupling agent is silane coupling agent KH550.

[0031] In some embodiments, the addition amount of the silane coupling agent is 3-5% of the mass of the nano-aluminum oxide.

[0032] In some embodiments, the iron-based powder is one or more of carbonyl iron powder, reduced iron powder, iron-silicon composite powder, and iron-silicon-chromium composite amorphous powder.

[0033] In some embodiments, the organic solvent is removed by stirring and evaporation.

[0034] In some embodiments, the addition amount of the lubricant is 0.1-0.4 wt% of the mass of the surface-coated soft magnetic metal powder material.

[0035] In some embodiments, the pressure used for pressing and forming is 900-1100 MPa.

[0036] In some embodiments, the heat treatment time is 30-60 min.

[0037] Preferably, the specific steps are as follows:

[0038] Step 1: Mix the silane coupling agent with deionized water, and adjust the pH to obtain a hydrolysis solution A;

[0039] Step 2: Mix nano-aluminum oxide, ethanol and water, and carry out ultrasonic dispersion to obtain a dispersion B;

[0040] Step 3: Add the hydrolysis solution A to the dispersion B, heat and stir, and carry out centrifugal separation. After drying, modified inorganic nano-powder is obtained;

[0041] Step 4: Mix the iron-based powder, the modified powder, the epoxy-modified silicone resin and the organic solvent to obtain a mixed solution C, stir until the organic solvent volatilizes, and obtain the surface-coated soft magnetic metal powder material after drying;

[0042] Step 5: Mix the powder prepared in Step 4 with the lubricant, carry out pressing and forming, and carry out heat treatment to obtain the product.

[0043] Another embodiment of the present invention provides an organic-inorganic composite-coated iron-based soft magnetic composite material obtained by the above preparation method.

[0044] The third embodiment of the present invention provides an application of the above organic-inorganic composite-coated iron-based soft magnetic composite material in an electric motor or a filter.

[0045] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific examples and comparative examples.

[0046] Example 1

[0047] A preparation method of an organic-inorganic composite-coated iron-based soft magnetic composite material is as Figure 1 shown, and includes the following steps:

[0048] (1) Weigh 0.15 g of silane coupling agent KH550 and mix it with 4 g of deionized water, and add glacial acetic acid dropwise to adjust the pH to about 3 to fully hydrolyze KH550.

[0049] (2) Weigh 5 g of nano-Al2O3 and put it into a flask, add 200 mL of ethanol / water mixed solution (ethanol∶water = 1:1, mass ratio) to the flask, and ultrasonically disperse for 30 min.

[0050] (3) After ultrasonic dispersion, add the hydrolyzed solution of KH550 to the dispersion, heat and stir with a magnetic stirrer at 80 °C for 4 h. After the reaction is completed, centrifuge and separate, and dry the separated powder at 80 °C for later use.

[0051] (4) Mix 50 g of reduced iron powder, 0.1 g of modified Al2O3, 0.9 g of epoxy-modified silicone resin (purchased from Hubei Longsheng Sihai New Materials Co., Ltd., 50% solid content) and xylene, and mechanically stir until the xylene volatilizes, and obtain a surface-coated soft magnetic metal powder material after drying.

[0052] (5) Add 0.1 wt% of zinc stearate as a lubricant to the dried powder, and cold press it at 1100 MPa. Heat-treat it in a tube furnace, the heat treatment temperature is 400 °C, the holding time is 30 min, and nitrogen is introduced as a protective gas. After the holding is completed, cool it to room temperature with the furnace, and finally obtain an organic-inorganic composite-coated iron-based soft magnetic composite material.

[0053] As Figure 2 shown, through EDS qualitative analysis of the iron powder surface, it can be found that elements such as Al and Si are more evenly distributed on the surface of the reduced iron powder, indicating that the epoxy-modified silicone resin and nano-aluminum oxide are successfully coated on the surface of the reduced iron powder, and the coating layer formed by this method has good formability.

[0054] It was measured that the saturation magnetization of the soft magnetic composite material obtained in Example 1 was 222.29 emu / g, the initial magnetic permeability was 55, and the loss was only 147 mW / g (100 KHz, 50 mT).

[0055] Example 2

[0056] A preparation method of an organic-inorganic composite-coated iron-based soft magnetic composite material, as Figure 1 shown, includes the following steps:

[0057] (1) Mix 0.15 g of silane coupling agent KH550 with 4 g of deionized water, adjust to a pH of about 3 with glacial acetic acid, and let KH550 hydrolyze fully.

[0058] (2) Weigh 5 g of nano-Al2O3 into a flask, add 200 mL of ethanol / water mixture (ethanol∶water = 1:1, mass ratio) to the flask, and ultrasonically disperse for 30 min.

[0059] (3) After ultrasonic dispersion, add the hydrolysis solution of KH550 to the dispersion, heat and stir with a magnetic stirrer at 80 °C for 4 h. After the reaction is completed, centrifuge and separate, and dry the separated powder at 80 °C for later use.

[0060] (4) Mix 50 g of reduced iron powder, 0.2 g of modified Al2O3, 0.8 g of epoxy-modified silicone resin and xylene, and mechanically stir until the xylene volatilizes, and obtain a surface-coated soft magnetic metal powder material after drying.

[0061] (5) Add 0.1 wt% of zinc stearate as a lubricant to the dried powder, and cold press and form at 1100 MPa. Heat-treat it in a tube furnace, the heat treatment temperature is 400 °C, the holding time is 30 min, introduce nitrogen as a protective gas, and cool it to room temperature with the furnace after the holding is over, and finally obtain an organic-inorganic composite-coated iron-based soft magnetic composite material.

[0062] It was measured that the saturation magnetization of the soft magnetic composite material obtained in Example 2 was 191.35 emu / g, the initial magnetic permeability was 52, and the loss was only 197.4 mW / g (100 KHz, 50 mT).

[0063] Example 3

[0064] A preparation method of an organic-inorganic composite-coated iron-based soft magnetic composite material, as Figure 1 shown, includes the following steps:

[0065] (1) Mix 0.15 g of silane coupling agent KH550 with 4 g of deionized water, adjust to a pH of about 3 with glacial acetic acid, and let KH550 hydrolyze fully.

[0066] (2) Weigh 5 g of nano - Al2O3 into a flask, add 200 mL of ethanol / water mixture (ethanol∶water = 1:1, mass ratio) to the flask, and ultrasonically disperse for 30 min.

[0067] (3) After ultrasonic dispersion, add the hydrolysis solution of KH550 to the dispersion, heat and stir with a magnetic stirrer at 80 °C for 4 h. After the reaction is completed, centrifuge and separate, and dry the separated powder at 80 °C for later use.

[0068] (4) Mix 50 g of reduced iron powder, 0.3 g of modified Al2O3, 0.7 g of epoxy - modified silicone resin and xylene, and mechanically stir until the xylene volatilizes. After drying, a surface - coated soft magnetic metal powder material is obtained.

[0069] (5) Add 0.1 wt% of zinc stearate as a lubricant to the dried powder, and cold - press and form it under 1100 MPa. Heat - treat it in a tubular furnace, the heat - treatment temperature is 400 °C, the holding time is 30 min, introduce nitrogen as a protective gas, and cool it to room temperature with the furnace after the holding is over. Finally, an organic - inorganic composite - coated iron - based soft magnetic composite material is obtained.

[0070] It is measured that the saturation magnetization intensity of the soft magnetic composite material obtained in Example 3 is 196.02 emu / g, the initial magnetic permeability is 51, and the loss is only 198.04 mW / g (100 KHz, 50 mT).

[0071] Figure 3 It shows that when the coating composition is 10% nano - alumina and 90% epoxy - modified silicone resin, the saturation magnetization intensity of the soft magnetic composite material is the highest. When the nano - alumina content is 10%, it can be more evenly distributed in the epoxy - modified silicone resin. Because when the alumina content is too high, agglomeration will occur in the epoxy - modified silicone resin, making the coating layer uneven and thus affecting the magnetic properties.

[0072] Example 4

[0073] A preparation method of an organic - inorganic composite - coated iron - based soft magnetic composite material, as Figure 1 shown, includes the following steps:

[0074] (1) Weigh 0.15 g of silane coupling agent KH550 and mix it with 4 g of deionized water, add glacial acetic acid dropwise to adjust the pH to about 3 to fully hydrolyze KH550.

[0075] (2) Weigh 5 g of nano - Al2O3 into a flask, add 200 mL of ethanol / water mixture (ethanol∶water = 1:1, mass ratio) to the flask, and ultrasonically disperse for 30 min.

[0076] (3) After ultrasonic dispersion, the hydrolysis solution of KH550 was added to the dispersion liquid, and it was heated and stirred with a magnetic stirrer at 80 °C for 2 h. After the reaction was completed, centrifugal separation was carried out, and the separated powder was dried at 80 °C for standby.

[0077] (4) 50 g of reduced iron powder, 0.1 g of modified Al2O3, 0.9 g of epoxy-modified silicone resin and xylene were mixed, and mechanically stirred until the xylene volatilized, and the surface-coated soft magnetic metal powder material was obtained by drying.

[0078] (5) 0.1 wt% of zinc stearate was added as a lubricant to the dried powder, and it was cold-pressed and formed at 1100 MPa. It was heat-treated in a tube furnace, the heat treatment temperature was 400 °C, the holding time was 30 min, nitrogen was introduced as a protective gas, and it was cooled to room temperature with the furnace after the holding was completed, and finally an organic-inorganic composite-coated iron-based soft magnetic composite material was obtained.

[0079] It was measured that the saturation magnetization intensity of the soft magnetic composite material obtained in Example 4 was 189.27 emu / g, the initial permeability was 51, and the loss was only 235.6 mW / g (100 KHz, 50 mT).

[0080] Example 5

[0081] A preparation method of an organic-inorganic composite-coated iron-based soft magnetic composite material, as Figure 1 shown, includes the following steps:

[0082] (1) Weigh 0.15 g of silane coupling agent KH550 and mix it with 4 g of deionized water, and dropwise add glacial acetic acid to adjust the pH to about 3 to fully hydrolyze KH550.

[0083] (2) Weigh 5 g of nano-Al2O3 and put it into a flask, add 200 mL of ethanol / water mixed solution (ethanol∶water = 1:1, mass ratio) to the flask, and ultrasonically disperse for 30 min.

[0084] (3) After ultrasonic dispersion, the hydrolysis solution of KH550 was added to the dispersion liquid, and it was heated and stirred with a magnetic stirrer at 80 °C for 3 h. After the reaction was completed, centrifugal separation was carried out, and the separated powder was dried at 80 °C for standby.

[0085] (4) 50 g of reduced iron powder, 0.1 g of modified Al2O3, 0.9 g of epoxy-modified silicone resin and xylene were mixed, and mechanically stirred until the xylene volatilized, and the surface-coated soft magnetic metal powder material was obtained by drying.

[0086] (5) 0.1 wt% of zinc stearate was added as a lubricant to the dried powder, and cold-pressed into a shape under 1100 MPa. It was heat-treated in a tube furnace at a heat treatment temperature of 400 °C for a holding time of 30 min, and nitrogen was introduced as a protective gas. After the holding was completed, it was cooled to room temperature with the furnace, and finally an organic-inorganic composite-coated iron-based soft magnetic composite material was obtained.

[0087] It was measured that the saturation magnetization of the soft magnetic composite material obtained in Example 5 was 187.53 emu / g, the initial permeability was 50, and the loss was only 238.5 mW / g (100 KHz, 50 mT).

[0088] Example 6

[0089] A preparation method of an organic-inorganic composite-coated iron-based soft magnetic composite material, as Figure 1 shown, includes the following steps:

[0090] (1) Weigh 0.15 g of silane coupling agent KH550 and mix it with 4 g of deionized water, and dropwise add glacial acetic acid to adjust the pH to about 3 to fully hydrolyze KH550.

[0091] (2) Weigh 5 g of nano-Al2O3 and put it into a flask, add 200 mL of ethanol / water mixture (ethanol∶water = 1:1, mass ratio) to the flask, and ultrasonically disperse for 30 min.

[0092] (3) After ultrasonic dispersion, add the hydrolyzed solution of KH550 to the dispersion, heat and stir with a magnetic stirrer at 60 °C for 4 h. After the reaction is completed, centrifuge and separate, and dry the separated powder at 80 °C for later use.

[0093] (4) Mix 50 g of reduced iron powder, 0.1 g of modified Al2O3, 0.9 g of epoxy-modified silicone resin and xylene, and mechanically stir until the xylene volatilizes, and obtain a surface-coated soft magnetic metal powder material after drying.

[0094] (5) 0.1 wt% of zinc stearate was added as a lubricant to the dried powder, and cold-pressed into a shape under 1100 MPa. It was heat-treated in a tube furnace at a heat treatment temperature of 400 °C for a holding time of 30 min, and nitrogen was introduced as a protective gas. After the holding was completed, it was cooled to room temperature with the furnace, and finally an organic-inorganic composite-coated iron-based soft magnetic composite material was obtained.

[0095] It was measured that the saturation magnetization of the soft magnetic composite material obtained in Example 6 was 189.58 emu / g, the initial permeability was 51, and the loss was only 224.42 mW / g (100 KHz, 50 mT).

[0096] Example 7

[0097] A preparation method of an organic-inorganic composite-coated iron-based soft magnetic composite material is as follows Figure 1 shown, and includes the following steps:

[0098] (1) Weigh 0.15 g of silane coupling agent KH550 and mix it with 4 g of deionized water, and dropwise add glacial acetic acid to adjust the pH to about 3 to fully hydrolyze KH550.

[0099] (2) Weigh 5 g of nano-Al2O3 and put it into a flask, add 200 mL of ethanol / water mixture (ethanol∶water = 1:1, mass ratio) to the flask, and ultrasonically disperse for 30 min.

[0100] (3) After ultrasonic dispersion, add the hydrolyzed solution of KH550 to the dispersion, heat and stir with a magnetic stirrer at 70 °C for 4 h. After the reaction is completed, centrifuge and separate, and dry the separated powder at 80 °C for standby.

[0101] (4) Mix 50 g of reduced iron powder, 0.1 g of modified Al2O3, 0.9 g of epoxy-modified silicone resin and xylene, and mechanically stir until the xylene volatilizes, and obtain a surface-coated soft magnetic metal powder material after drying.

[0102] (5) Add 0.1 wt% of zinc stearate as a lubricant to the dried powder, and cold press and mold it at 1100 MPa. Heat-treat it in a tube furnace, the heat treatment temperature is 400 °C, the holding time is 30 min, introduce nitrogen as a protective gas, and cool it to room temperature with the furnace after the holding is completed, and finally obtain an organic-inorganic composite-coated iron-based soft magnetic composite material.

[0103] It is measured that the saturation magnetization intensity of the soft magnetic composite material obtained in Example 7 is 193.74 emu / g, the initial magnetic permeability is 51, and the loss is only 214.25 mW / g (100 KHz, 50 mT).

[0104] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of an organic-inorganic composite-coated iron-based soft magnetic composite material, characterized in that The nano-aluminum oxide is modified with a silane coupling agent to obtain modified aluminum oxide; the iron-based powder, modified aluminum oxide, epoxy-modified silicone resin and organic solvent are mixed uniformly, and after removing the organic solvent, a surface-coated soft magnetic metal powder material is obtained; the surface-coated soft magnetic metal powder material is mixed with a lubricant and then pressed into a shape, and then heat-treated at 300-500 °C to obtain the product; Among them, the mass ratio of the iron-based powder, modified aluminum oxide, and epoxy-modified silicone resin is 100:0.2-0.6:1.4-1.

8.

2. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 1, characterized in that, The modified aluminum oxide is 9-11% of the total mass of the modified aluminum oxide and the epoxy-modified silicone resin.

3. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 1, characterized in that, The process of modifying nano-aluminum oxide with a silane coupling agent to obtain modified aluminum oxide is as follows: the silane coupling agent is hydrolyzed, and then the hydrolyzed silane coupling agent is coupled with nano-aluminum oxide to obtain modified aluminum oxide; Or, the process of modifying nano-aluminum oxide with a silane coupling agent to obtain modified aluminum oxide is as follows: the silane coupling agent is hydrolyzed to obtain a hydrolyzed solution, the hydrolyzed solution is mixed with a nano-aluminum oxide dispersion, heated to 70-90 °C for reaction, and centrifuged to obtain modified aluminum oxide.

4. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 3, characterized in that, The silane coupling agent is added to water, and the pH is adjusted to 3-4 to obtain a hydrolyzed solution.

5. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 4, characterized in that Acetic acid is used to adjust the pH.

6. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 3, characterized in that The nano-aluminum oxide is mixed uniformly with ethanol and water, and ultrasonically treated to obtain a nano-aluminum oxide dispersion.

7. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 6, characterized in that, The mass-volume ratio of nano-aluminum oxide to the liquid is 2.0-3.0:100, g: mL.

8. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 3, characterized in that, The heating reaction time is 3-5 h.

9. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 1, characterized in that, The silane coupling agent is silane coupling agent KH550.

10. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 1, characterized in that, The iron-based powder is one or more of carbonyl iron powder, reduced iron powder, iron-silicon composite powder, and iron-silicon-chromium composite amorphous powder.

11. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 1, characterized in that, The addition amount of the silane coupling agent is 3-5% of the mass of the nano-aluminum oxide.

12. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 1, characterized in that, The addition amount of the lubricant is 0.1-0.4 wt% of the mass of the surface-coated soft magnetic metal powder material.

13. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 1, characterized in that, The organic solvent is removed by stirring and evaporation.

14. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 1, characterized in that, The pressure used for pressing into a shape is 900-1100 MPa.

15. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 1, characterized in that, The heat treatment time is 30-60 min.

16. The preparation method of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 1, characterized in that, The specific steps are as follows: Step 1: Mix the silane coupling agent with deionized water, and adjust the pH to obtain a hydrolyzed solution A; Step 2: Mix the nano-aluminum oxide, ethanol and water and perform ultrasonic dispersion to obtain a dispersion B; Step 3: Add the hydrolyzed solution A to the dispersion B, heat and stir, centrifuge, and dry to obtain modified inorganic nano-powder; Step 4: Mix the iron-based powder, modified powder, epoxy-modified silicone resin and organic solvent to obtain a mixed solution C, stir until the organic solvent volatilizes, and dry to obtain a surface-coated soft magnetic metal powder material; Step 5: Mix the powder prepared in Step 4 with a lubricant, press into a shape, and perform heat treatment to obtain the product.

17. An organic-inorganic composite-coated iron-based soft magnetic composite material, characterized in that, Obtained by the preparation method according to any one of claims 1-16.

18. An application of the organic-inorganic composite-coated iron-based soft magnetic composite material according to claim 17 in an electric motor or a filter.

Images