阅读说明：本技术 一种铁氧体包覆FeSiAl金属磁粉芯及其制备方法 (Ferrite-coated FeSiAl metal magnetic powder core and preparation method thereof ) 是由 张雪峰 刘先国 李忠 李红霞 孙玉萍 于 2020-11-11 设计创作，主要内容包括：本发明涉及磁性材料技术领域,尤其涉及一种铁氧体包覆FeSiAl金属磁粉芯及其制备方法,包括以下步骤：(1)将FeSiAl金属软磁粉和可溶性铁盐的水溶液混合,加热搅拌后,烘干；(2)和可溶性氢氧化物溶液混合,常温搅拌后,烘干；(3)与粘结剂和润滑剂混合均匀,压制成型,得坯体；(4)将坯体在真空或氮气或氢气中进行热处理,冷却,喷涂,即得铁氧体包覆FeSiAl金属磁粉芯。本发明通过化学共沉积法FeSiAl金属软磁粉外表面形成均匀的铁氢氧化物层,然后经过压制成型和高温热处理,铁氢氧化物层转变为致密均匀的铁氧体绝缘层,避免了铁氧体绝缘层在压制过程中的破裂,外层的铁氧体绝缘层为铁磁性的,可以降低磁稀释作用,进一步提升复合材料的磁性能。(The invention relates to the technical field of magnetic materials, in particular to a ferrite-coated FeSiAl metal magnetic powder core and a preparation method thereof, wherein the ferrite-coated FeSiAl metal magnetic powder core comprises the following steps: (1) mixing FeSiAl metal soft magnetic powder and a soluble ferric salt water solution, heating and stirring, and drying; (2) mixing with soluble hydroxide solution, stirring at normal temperature, and drying; (3) mixing with binder and lubricant, and press molding to obtain blank; (4) and (3) carrying out heat treatment on the blank in vacuum or nitrogen or hydrogen, cooling and spraying to obtain the ferrite-coated FeSiAl metal magnetic powder core. According to the invention, a uniform ferric hydroxide layer is formed on the outer surface of the FeSiAl metal soft magnetic powder by a chemical codeposition method, and then the ferric hydroxide layer is converted into a compact and uniform ferrite insulating layer through compression molding and high-temperature heat treatment, so that the cracking of the ferrite insulating layer in the compression process is avoided, the outer ferrite insulating layer is ferromagnetic, the magnetic dilution effect can be reduced, and the magnetic performance of the composite material is further improved.)

1. A preparation method of a ferrite-coated FeSiAl metal magnetic powder core is characterized by comprising the following steps:

(1) mixing FeSiAl soft metal powder with an aqueous solution of soluble ferric salt, heating and stirring uniformly, and drying to obtain FeSiAl soft metal powder @ ferric salt;

(2) mixing the FeSiAl metal soft magnetic powder @ ferric salt obtained in the step (1) with a soluble hydroxide solution, stirring uniformly at normal temperature, and drying to obtain insulating metal soft magnetic powder;

(3) uniformly mixing the insulated metal soft magnetic powder obtained in the step (2) with a binder and a lubricant, and performing compression molding to obtain a blank;

(4) and (4) carrying out heat treatment on the blank obtained in the step (3) in vacuum or nitrogen or hydrogen, cooling and spraying to obtain the ferrite-coated FeSiAl metal magnetic powder core.

2. The method for preparing a ferrite-coated FeSiAl metal magnetic powder core as claimed in claim 1, wherein in step (1), the soluble iron salt is selected from FeCl₂、FeSO₄And Fe (NO)₃)₂One or more of them are mixed.

3. The method for preparing the ferrite-coated FeSiAl metal magnetic powder core according to claim 1, wherein in the step (1), the heating and stirring temperature is 80-00 ℃ and the time is 20-40 min; in the step (1) and the step (2), the drying temperature is 90-120 ℃, and the time is 20-40 min.

4. The method for preparing a ferrite-coated FeSiAl metal magnetic powder core as claimed in claim 1, wherein in step (2), the soluble hydroxide is selected from NaOH, KOH, Ba (OH)₂And Ca (OH)₂One kind of (1).

5. The method for preparing the ferrite-coated FeSiAl metal magnetic powder core according to claim 1, wherein the addition amount of the soluble iron salt is 1-3 wt% based on the total mass of the FeSiAl metal soft magnetic powder; the amount of the soluble hydroxide added is 1 to 3 wt%.

6. The method for preparing a ferrite-coated FeSiAl metal magnetic powder core as claimed in claim 1, wherein in the step (3), the binder is selected from one or more of epoxy resin, silicone resin, silica, glass powder and water glass; the addition amount of the binder is 0.5-1 wt% based on the total mass of the FeSiAl metal soft magnetic powder.

7. The method for preparing a ferrite coated FeSiAl metal magnetic powder core as claimed in claim 1, wherein in the step (3), the lubricant is one or two selected from zinc stearate and barium stearate; the addition amount of the lubricant is 0.5-1 wt% based on the total mass of the FeSiAl metal soft magnetic powder.

8. The method for preparing a ferrite coated FeSiAl metal magnetic powder core as claimed in claim 1, wherein in the step (3), the pressure for press forming is 1500-2000 MPa.

9. The method for preparing a ferrite-coated FeSiAl metal magnetic powder core as claimed in claim 1, wherein in the step (4), the heat treatment temperature is 600-750 ℃ and the time is 0.5-2 h.

10. A ferrite-coated fesai metal magnetic powder core prepared by the process of any of claims 1-9.

Technical Field

The invention relates to the technical field of magnetic material manufacturing, in particular to a ferrite-coated FeSiAl metal magnetic powder core and a preparation method thereof.

Background

The soft magnetic metal powder core is one new kind of composite material comprising ferromagnetic grains and insulating medium. The metal soft magnetic powder core has the advantages of high saturation magnetic induction intensity, effective magnetic conductivity, low loss, good direct current bias performance, frequency stability and the like, and is widely applied to various electronic devices.

The insulation coating is a key process of the metal magnetic powder core and mainly comprises organic insulation coating and inorganic insulation coating. Because the organic matter can not resist high temperature annealing, and the organic coated magnetic powder core can be aged after long-time working. Thus, the inorganic insulating coating process is currently the predominant coating process, including phosphate passivation coating (zinc, iron and manganese phosphates) and oxide coating (SiO)₂MgO, ferrite, etc.).

The biggest problem of the phosphate passivation coating is that as the heat treatment temperature is increased to above 700 ℃, the phosphate insulating layer is gradually decomposed, so that the resistivity is sharply reduced, and the loss of the magnetic powder core is rapidly increased. The heat treatment temperature is lowered, and phosphate decomposition can be avoided, but the internal stress generated in the pressing process cannot be effectively released, so that the magnetic permeability is reduced. The non-magnetic oxide has extremely high resistivity, can effectively reduce eddy current loss, has higher heat-resistant temperature and can meet the requirement of high-temperature heat treatment. However, the nonmagnetic oxide has a magnetic dilution effect, and the nonmagnetic substance greatly lowers the saturation magnetization and permeability of the magnetic powder core, deteriorating the magnetic properties of the magnetic powder core. Although ferrite can solve the magnetic dilution effect, the process is complex, the cost is high, and the ferrite is not beneficial to industrial production. In order to obtain a high-performance iron-silicon-based soft magnetic powder core with high magnetic permeability and low loss, improvement of a coating and preparation process of the iron-silicon-based magnetic powder core is urgently needed.

Chinese patent literature discloses an iron-silicon alloy magnetic powder core and a manufacturing method thereof, and the application publication number is CN102314986A, the iron-silicon alloy magnetic powder is heated to 50-150 ℃, then phosphoric acid with the weight concentration of 0.8-3.2% is added for surface passivation, after drying, 0.3-1.5% of phenolic resin is added, and after drying again, pressing forming and heat treatment, the iron-silicon metal soft magnetic powder core is obtained. However, this method has a problem that the phosphate insulating layer is gradually decomposed during heat treatment, resulting in a sharp decrease in resistivity, a rapid increase in magnetic powder core loss, and aging.

Chinese patent literature discloses a method for preparing a metal soft magnetic powder core, the application publication number of which is CN103247403A, the invention selects nano oxide dispersion liquid to carry out insulation coating on metal magnetic powder, wherein MgO nano particles account for 5-35% of the total weight of the dispersion liquid. Because the dispersion liquid has poor stability and the MgO nano-particles have poor adhesion to magnetic powder, uniform coating is difficult to realize and the MgO nano-particles are easy to fall off, the insulation performance is poor, and the eddy current loss is large.

Chinese patent literature discloses a magnetic powder core material with stable magnetic conductivity and low loss and a preparation method thereof, and the application publication number is CN 108335820A. However, in the preparation process of the invention, the composite powder has large internal stress, and a high heat treatment temperature is required, so that the magnetic powder is further oxidized, and the magnetic permeability is greatly reduced at high frequency.

Chinese patent literature discloses a composite magnetic powder core and a preparation method thereof, the application publication number of the composite magnetic powder core is CN109887698A, and the invention respectively adopts deionized water and acetone to clean FeSiCr magnetic powder; secondly, preparing NiZn ferrite by adopting a solid-phase sintering method, and performing powder ball milling to obtain a ferrite coating agent; and thirdly, stirring the FeSiCr magnetic powder and the ferrite coating agent, drying, pressing and carrying out heat treatment to obtain the magnetic powder core. However, the ferrite obtained by this method has poor coating effect and poor insulating property.

Chinese patent literature discloses a method for preparing a FeSiAl/Mn-Zn ferrite composite magnetic powder core, the application publication number of which is CN106373697A, the method takes iron salt, zinc salt and manganese salt as raw materials, NaOH solution as a precipitator, a Mn-Zn ferrite precursor is synthesized on the surface of magnetic powder in situ by a chemical codeposition method, the FeSiAl/Mn-Zn ferrite composite magnetic powder is obtained by roasting at 900 ℃ for 1 to 2 hours at 800 ℃ and 720 ℃ and is pressed and subjected to heat treatment at 600 ℃ and 720 ℃ to obtain the magnetic powder core. However, the method has a high-temperature roasting process, and is not beneficial to reducing energy consumption and large-scale industrial production. And the formed Mn-Zn ferrite insulating layer is easily broken during pressing, resulting in an increase in eddy current loss.

Disclosure of Invention

The invention provides a preparation method of a ferrite-coated FeSiAl metal magnetic powder core in order to overcome the problems in the prior art, and the method is simple to operate, free of pollution, low in cost and suitable for industrial production.

The invention also provides the ferrite-coated FeSiAl metal magnetic powder core prepared by the preparation method, the ferrite-coated FeSiAl metal magnetic powder core has the characteristics of low loss, high magnetic conductivity and good bonding strength, the prepared insulating layer is thin, the magnetic dilution effect is reduced, and the high-frequency stability of the metal magnetic powder core is enhanced on the premise of not obviously reducing the magnetic performance.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a ferrite-coated FeSiAl metal magnetic powder core is characterized by comprising the following steps:

(1) mixing FeSiAl soft metal powder with an aqueous solution of soluble ferric salt, heating and stirring uniformly, and drying to obtain FeSiAl soft metal powder @ ferric salt;

(2) mixing the FeSiAl metal soft magnetic powder @ ferric salt obtained in the step (1) with a soluble hydroxide solution, stirring uniformly at normal temperature (20-40 ℃), and drying to obtain insulated metal soft magnetic powder;

(3) uniformly mixing the insulated metal soft magnetic powder obtained in the step (2) with a binder and a lubricant, and performing compression molding to obtain a blank;

(4) and (4) carrying out heat treatment on the blank obtained in the step (3) in vacuum (the vacuum degree is less than 10Pa) or nitrogen or hydrogen, cooling and spraying to obtain the ferrite-coated FeSiAl metal magnetic powder core. The step has high strength after heat treatment, the comprehensive performance of the product is good, the high-temperature roasting of the ferrite precursor by the traditional chemical coprecipitation method is avoided, the high-temperature roasting and the heat treatment process are creatively integrated, and the energy consumption is reduced.

According to the invention, a uniform ferric hydroxide layer is formed on the surface of the magnetic powder by a chemical codeposition method, and then the ferric hydroxide layer is converted into a compact and uniform ferrite insulating layer through compression molding and high-temperature heat treatment, so that the ferrite insulating layer is prevented from cracking in the compression process, the resistivity of the magnetic powder core is improved, the high-temperature heat treatment is favorable for releasing the internal stress in a blank, and the loss of the magnetic powder core is greatly reduced; meanwhile, the outer ferrite insulating layer is ferromagnetic, so that the magnetic dilution effect can be reduced, and the magnetic performance of the composite material is further improved. The preparation method disclosed by the invention is simple to operate, free of pollution, low in cost and suitable for industrial large-scale production.

Preferably, the chemical formula of the FeSiAl metal soft magnetic powder is Fe₈₅Si_9.6Al_5.4。

Preferably, in step (1), the soluble iron salt is selected from FeCl₂、FeSO₄And Fe (NO)₃)₂One or more of them are mixed. The soluble iron salts of the invention all contain Fe²⁺The method has the function of forming a soluble iron salt coating layer on the surface of the FeSiAl metal soft magnetic powder.

Preferably, in the step (1), the heating and stirring temperature is 80-00 ℃ and the time is 20-40 min; the drying temperature is 90-120 ℃, and the drying time is 20-40 min.

Preferably, in step (2), the soluble hydroxide is selected from NaOH, KOH, Ba (OH)₂And Ca (OH)₂One kind of (1). The present invention utilizes the OH of the soluble hydroxide^-And (2) forming an iron hydroxide layer on the surface of the @ ferric salt in the step (1), and then converting the iron hydroxide layer into a compact and uniform ferrite insulating layer through compression molding and high-temperature heat treatment.

Preferably, in the step (1), the addition amount of the soluble ferric salt is 1-3 wt% based on the total mass of the FeSiAl metal soft magnetic powder; the addition amount of the soluble ferric salt is critical, the poor insulation property of the composite soft magnetic powder can be caused by the excessively low addition amount, the high loss can be caused, and the magnetic conductivity of the FeSiAl metal soft magnetic powder can be reduced by the excessively high addition amount.

Preferably, in the step (2), the addition amount of the soluble hydroxide is 1-3 wt% based on the total mass of the FeSiAl metal soft magnetic powder; the amount of soluble hydroxide solution added is critical, and too low an amount results in failure to form a uniform iron hydroxide coating layer, and too high an amount results in excessive corrosion of the magnetic powder core.

Preferably, in the step (2), the drying temperature is 90-120 ℃ and the time is 20-40 min.

Preferably, in the step (3), the binder is selected from one or more of epoxy resin, silicone resin, silica, glass powder and water glass; the addition amount of the binder is 0.5-1 wt% based on the total mass of the FeSiAl metal soft magnetic powder. The low addition of the binder can lead to poor binding property of the FeSiAl magnetic powder, and the high addition of the binder can lead to reduction of magnetic permeability of the FeSiAl magnetic powder.

Preferably, in the step (3), the lubricant is selected from one or two of zinc stearate and barium stearate; the addition amount of the lubricant is 0.5-1 wt% based on the total mass of the FeSiAl metal soft magnetic powder.

Preferably, in the step (3), the pressure of the compression molding is 1500-2000 MPa.

Preferably, in the step (4), the heat treatment temperature is 600-750 ℃ and the time is 0.5-2 h. The heat treatment temperature is critical, the internal stress generated in the pressing process cannot be released due to too low heat treatment temperature, the magnetic performance cannot reach the optimal value, and the binding agent is damaged due to too high heat treatment temperature, so that the FeSiAl magnetic powder is further oxidized. The conversion rate of the iron hydroxide can be controlled by the heat treatment temperature, and the resistivity can be regulated.

The ferrite-coated FeSiAl metal magnetic powder core prepared by the preparation method.

The insulating layer of the ferrite-coated FeSiAl metal magnetic powder core prepared by the process is thin, the magnetic dilution effect is reduced, and the high-frequency stability of the ferrite-coated FeSiAl metal magnetic powder core is enhanced on the premise of not obviously reducing the magnetic performance; the ferrite-coated FeSiAl metal magnetic powder core has the characteristics of low loss, high magnetic conductivity and good bonding strength, and can solve the problem of large eddy current loss of the FeSiAl metal magnetic powder core at medium-high frequency.

Therefore, the invention has the following beneficial effects:

(1) the preparation method has the advantages of simple operation, low cost and no pollution to the environment, and is suitable for large-scale industrial production; the uniform ferric hydroxide layer is formed on the outer surface of the FeSiAl metal soft magnetic powder by a chemical codeposition method, then the ferric hydroxide layer is converted into a compact and uniform ferrite insulating layer through compression molding and high-temperature heat treatment, so that the cracking of the ferrite insulating layer in the compression process is avoided, the outer ferrite insulating layer is ferromagnetic, the magnetic dilution effect can be reduced, and the magnetic performance of the composite material is further improved;

(2) the high-temperature roasting of ferrite precursors by the traditional chemical coprecipitation method is avoided, the high-temperature roasting and the heat treatment process are creatively integrated, the energy consumption is reduced, and meanwhile, the conversion rate of iron hydroxide can be controlled and the resistivity can be regulated and controlled through the heat treatment temperature;

(3) the insulating layer of the ferrite-coated FeSiAl metal magnetic powder core prepared by the process is thin, the magnetic dilution effect is reduced, and the high-frequency stability of the ferrite-coated FeSiAl metal magnetic powder core is enhanced on the premise of not obviously reducing the magnetic performance; the ferrite-coated FeSiAl metal magnetic powder core has the characteristics of low loss, high magnetic conductivity and good bonding strength, and can solve the problem of large eddy current loss of the FeSiAl metal magnetic powder core at medium-high frequency.

Detailed Description

The technical solution of the present invention is further specifically described below by way of specific examples.

In the present invention, all the equipment and materials are commercially available or commonly used in the art, and the methods in the following examples are conventional in the art unless otherwise specified.

Example 1

(1) FeSiAl metal soft magnetic powder and FeCl₂The temperature is raised to 80 ℃, and the mixture is heated and stirred for 20min, so that a layer of soluble FeCl is formed on the surface of the FeSiAl metal soft magnetic powder₂Keeping the temperature at 90 ℃ for 20min and drying to obtain FeSiAl metal soft magnetic powder @ FeCl₂(ii) a Taking the total mass of FeSiAl metal soft magnetic powder as a reference, FeCl₂The addition amount of (B) is 1 wt%;

(2) the FeSiAl metal soft magnetic powder @ FeCl obtained in the step (1)₂Mixing with NaOH solution, stirring uniformly at normal temperature (20 ℃), and then keeping the temperature at 90 ℃ for 20min to dry to obtain insulated metal soft magnetic powder; taking the total mass of the FeSiAl metal soft magnetic powder as a reference, and the addition amount of NaOH is 2 wt%;

(3) uniformly mixing the insulated metal soft magnetic powder obtained in the step (2) with epoxy resin and zinc stearate, and performing compression molding under the pressure of 1500MPa to obtain a blank with the outer diameter of 33.00mm, the inner diameter of 19.90mm and the height of 10.7 mm; taking the total mass of the FeSiAl metal soft magnetic powder as a reference, the adding amount of the epoxy resin is 0.5 wt%, and the adding amount of the zinc stearate is 0.5 wt%;

(4) and (3) carrying out heat treatment on the blank obtained in the step (3) in vacuum (the vacuum degree is 10Pa), cooling and spraying at the heat treatment temperature of 600 ℃ for 0.5h to obtain the ferrite-coated FeSiAl metal magnetic powder core, wherein the tested magnetic parameters are shown as follows.

Example 2

(1) FeSiAl metal soft magnetic powder and FeCl₂The temperature is raised to 100 ℃, and the mixture is heated and stirred for 40min, so that a layer of soluble FeCl is formed on the surface of the FeSiAl metal soft magnetic powder₂Keeping the temperature at 120 ℃ for 40min and drying to obtain FeSiAl metal soft magnetic powder @ FeCl₂(ii) a Taking the total mass of FeSiAl metal soft magnetic powder as a reference, FeCl₂The addition amount of (B) is 3 wt%;

(2) the FeSiAl metal soft magnetic powder @ FeCl obtained in the step (1)₂Mixing with NaOH solution, stirring uniformly at normal temperature (40 ℃), and then keeping the temperature at 120 ℃ for 40min to dry to obtain insulated metal soft magnetic powder; the addition amount of NaOH is 3 wt% based on the total mass of the FeSiAl metal soft magnetic powder;

(3) uniformly mixing the insulated metal soft magnetic powder obtained in the step (2) with epoxy resin and zinc stearate, and performing compression molding under the pressure of 2000MPa to obtain a blank with the outer diameter of 33.00mm, the inner diameter of 19.90mm and the height of 10.7 mm; taking the total mass of the FeSiAl metal soft magnetic powder as a reference, the adding amount of the epoxy resin is 0.5-1 wt%, and the adding amount of the zinc stearate is 0.5-1 wt%;

(4) and (4) carrying out heat treatment on the blank obtained in the step (3) in hydrogen at the temperature of 600 ℃ for 0.5h, cooling and spraying to obtain the ferrite-coated FeSiAl metal magnetic powder core, wherein the tested magnetic parameters are shown as follows.

Example 3

(1) FeSiAl metal soft magnetic powder and FeSO₄The aqueous solution is mixed, heated to 80 ℃, heated and stirred for 20min, so that a layer of soluble FeSO is formed on the surface of the FeSiAl metal soft magnetic powder₄Keeping the temperature at 90 ℃ for 20min and drying to obtain FeSiAl metal soft magnetic powder @ FeSO₄(ii) a FeSO based on the total mass of FeSiAl metal soft magnetic powder₄The addition amount of (B) is 1 wt%;

(2) the FeSiAl metal soft magnetic powder @ FeCl obtained in the step (1)₂Mixing with KOH solution, stirring at normal temperature, and oven drying at 90 deg.C for 20min to obtain insulated metal soft magnetic powder; taking the total mass of the FeSiAl metal soft magnetic powder as a reference, and the addition amount of KOH is 2 wt%;

(3) uniformly mixing the insulated metal soft magnetic powder obtained in the step (2) with water glass, barium stearate and zinc stearate, and performing compression molding under the pressure of 1500-2000 MPa to obtain a blank with the outer diameter of 33.00mm, the inner diameter of 19.90mm and the height of 10.7 m; taking the total mass of the FeSiAl metal soft magnetic powder as a reference, the adding amount of the water glass is 0.5 wt%, the adding amount of the zinc stearate is 0.2 wt%, and the adding amount of the barium stearate is 0.3 wt%;

(4) and (3) carrying out heat treatment on the blank obtained in the step (3) in vacuum (the vacuum degree is 1Pa), cooling and spraying at the heat treatment temperature of 700 ℃ for 0.5h to obtain the ferrite-coated FeSiAl metal magnetic powder core, wherein the tested magnetic parameters are shown as follows.

Example 4

(1) FeSiAl metal soft magnetic powder and FeSO₄The aqueous solution is mixed, heated to 100 ℃, heated and stirred for 40min, so that a layer of soluble FeSO is formed on the surface of the FeSiAl metal soft magnetic powder₄Keeping the temperature at 120 ℃ for 40min and drying to obtain FeSiAl metal soft magnetic powder @ FeSO₄(ii) a FeSO based on the total mass of FeSiAl metal soft magnetic powder₄The addition amount of (B) is 2 wt%;

(2) the FeSiAl metal soft magnetic powder @ FeSO obtained in the step (1)₄Mixing with NaOH solution, stirring uniformly at normal temperature (30 ℃), and then keeping the temperature at 100 ℃ for 30min to dry to obtain insulated metal soft magnetic powder; taking the total mass of the FeSiAl metal soft magnetic powder as a reference, and the addition amount of NaOH is 2 wt%;

(3) uniformly mixing the insulated metal soft magnetic powder obtained in the step (2) with silicon dioxide, epoxy resin and zinc stearate, and pressing and forming under the pressure of 1800MPa to obtain a blank with the outer diameter of 33.00mm, the inner diameter of 19.90mm and the height of 10.7 mm; taking the total mass of the FeSiAl metal soft magnetic powder as a reference, the adding amount of silicon dioxide is 0.4 wt%, the adding amount of epoxy resin is 0.4 wt%, and the adding amount of zinc stearate is 1 wt%;

(4) and (4) carrying out heat treatment on the blank obtained in the step (3) in nitrogen at the temperature of 730 ℃ for 2 hours, cooling and spraying to obtain the ferrite-coated FeSiAl metal magnetic powder core, wherein the tested magnetic parameters are shown as follows.

Example 5

(1) Mixing FeSiAl metal soft magnetic powder and Fe (NO)₃)₂The temperature is raised to 90 ℃, and the mixture is heated and stirred for 20min, so that a layer of soluble Fe (NO) is formed on the surface of the FeSiAl metal soft magnetic powder₃)₂Keeping the temperature at 100 ℃ for 30min and drying to obtain FeSiAl metal soft magnetic powder @ Fe (NO)₃)₂(ii) a Fe (NO) based on the total mass of FeSiAl metal soft magnetic powder₃)₂The addition amount of (B) is 2 wt%;

(2) the FeSiAl metal soft magnetic powder @ Fe (NO) obtained in the step (1)₃)₂And Ba (OH)₂Mixing the solutions, stirring at normal temperature (30 ℃) for 30min, and then keeping the temperature at 120 ℃ for 30min and drying to obtain insulated metal soft magnetic powder; ba (OH) based on the total mass of FeSiAl metal soft magnetic powder₂The addition amount of (B) is 2 wt%;

(3) uniformly mixing the insulated metal soft magnetic powder obtained in the step (2) with silicone resin and barium stearate, and performing compression molding under the pressure of 1700MPa to obtain a blank with the outer diameter of 33.00mm, the inner diameter of 19.90mm and the height of 10.7 mm; taking the total mass of the FeSiAl metal soft magnetic powder as a reference, the adding amount of the silicone resin is 0.9 wt%, and the adding amount of the barium stearate is 0.9 wt%;

(4) and (4) carrying out heat treatment on the blank obtained in the step (3) in hydrogen at the heat treatment temperature of 750 ℃ for 1h, cooling and spraying to obtain the ferrite-coated FeSiAl metal magnetic powder core, wherein the tested magnetic parameters are shown as follows.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.