阅读说明：本技术 铁硅铝软磁粉芯及其制备方法 (Fe-Si-Al soft magnetic powder core and preparation method thereof ) 是由 董亚强 陆浩 贺爱娜 黎嘉威 于 2021-07-05 设计创作，主要内容包括：本发明提供了一种铁硅铝软磁粉芯的制备方法,其通过选用铁硅铝磁粉,创造性的设计了磷酸盐-硅烷-含硅芳炔树脂三层包覆结构,将有机包覆与无机包覆相结合,实现了磁粉的均匀包覆,能够使材料的耐温性能大幅提升,相对于现有的包覆材料进一步提升了磁粉的退火温度,制备出了有效磁导率可达66的铁硅铝软磁粉芯,具备优异的软磁性能,尤其是软磁粉芯的直流性能得到大幅度提升,在100Oe条件下的粉芯直流偏置性能高于55％,在50kHz、100mT条件下体积损耗低于170mW/cm～(3)。(The invention provides a preparation method of a Fe-Si-Al soft magnetic powder core, which is characterized in that Fe-Si-Al magnetic powder is selected, a phosphate-silane-Si-containing aryne resin three-layer coating structure is creatively designed, organic coating and inorganic coating are combined, uniform coating of the magnetic powder is realized, the temperature resistance of the material can be greatly improved, the annealing temperature of the magnetic powder is further improved compared with the existing coating material, the Fe-Si-Al soft magnetic powder core with the effective magnetic conductivity of 66 is prepared, the Fe-Si-Al soft magnetic powder core has excellent soft magnetic performance, particularly the direct current performance of the soft magnetic powder core is greatly improved, the direct current bias performance of the powder core under the condition of 100Oe is higher than 55%, and the volume loss is lower than 170mW/cm under the conditions of 50kHz and 100mT 3 。)

1. The Fe-Si-Al soft magnetic powder core consists of Fe-Si-Al magnetic powder and a coating layer of phosphate, silane and silicon-containing aryne resin on the surface of the magnetic powder in sequence.

2. The method for preparing sendust soft magnetic powder core as recited in claim 1, comprising the steps of:

A) mixing the iron-silicon-aluminum magnetic powder with a phosphoric acid solution, heating for reaction, and drying to obtain phosphate-coated iron-silicon-aluminum powder; the Fe-Si-Al magnetic powder comprises 5.0-15.0 wt% of Si, 3.0-10.0 wt% of Al and the balance of Fe;

B) mixing the powder of the phosphate-coated Fe-Si-Al with silane hydrolysate, reacting to obtain Fe-Si-Al magnetic powder with a phosphate-silane coating layer, mixing the Fe-Si-Al magnetic powder with the phosphate-silane coating layer with silicon-containing aryne resin solution, and reacting to obtain magnetic powder with the phosphate-silane-silicon-containing aryne resin coating layer;

C) mixing the magnetic powder obtained in the step B) with a binder and a release agent, and pressing to obtain a molded magnetic core;

carrying out heat treatment on the formed magnetic core to obtain a semi-finished magnetic core;

D) and spraying a coating on the surface of the semi-finished magnetic core to obtain the metal soft magnetic powder core.

3. The method according to claim 2, wherein phosphoric acid in the phosphoric acid solution is 0.05 to 2 wt% of the sendust powder, and ethanol is 2 to 5 wt% of the sendust powder.

4. The method according to claim 2, wherein the silane hydrolysate is selected from one or two of an alcohol solution of silane and an aqueous solution of silane, and the silane in the silane hydrolysate is selected from one or more of gamma- (2, 3 glycidoxy) propyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, and 3-aminopropyltriethoxysilane.

5. The method of claim 2, wherein the binder is selected from one or more of a siloxane resin, a phenol resin, a polyamide resin sodium silicate, lithium silicate, aluminum silicate, an epoxy resin, and a silicone resin; the release agent is selected from one or more of zinc stearate, calcium stearate, talcum powder and mica powder.

6. The preparation method according to claim 2, wherein the silicon-containing aryne resin solution is an acetone solution of silicon-containing aryne resin, and the amount of the silicon-containing aryne resin is 1-5 wt% of the sendust powder with the phosphate-silane coating layer.

7. The preparation method according to claim 2, wherein the pressing pressure is 1500-2500 MPa, the heat treatment temperature is 550-850 ℃, and the holding time is 30-150 min.

8. The production method according to claim 2, wherein in the step C), the binder is 0.1 to 0.9 wt% of the magnetic powder, and the release agent is 0.3 to 1.0 wt% of the magnetic powder.

9. The method according to claim 2, wherein the heating temperature in step A) is 50 to 100 ℃.

10. The preparation method according to any one of claims 2 to 9, wherein in the step a), the sendust magnetic powder is a gas atomized sendust magnetic powder with a particle size of-200 meshes.

Technical Field

The invention relates to the technical field of soft magnetic materials, in particular to a preparation method of an iron-silicon-aluminum soft magnetic powder core.

Background

The market scale of the inductor industry in China reaches 220.2 billion yuan by 2024 years. Wherein, the sendust core occupies more than 80% of the market in the civil field due to its excellent soft magnetic performance; however, the saturation magnetic induction is low, and the dc bias characteristic is poor, so that the application of the dc bias to high-end products is limited. Therefore, how to improve the saturation magnetic induction intensity of the iron-silicon-aluminum alloy based on the existing iron-silicon-aluminum alloy system through methods of alloy component optimization, second phase compounding and the like, and the method reduces the loss and improves the performance stability through the optimization of the preparation process, and is the development direction of the iron-silicon-aluminum magnetic powder core.

Chinese patent publication No. CN104795195A discloses a method for preparing a sendust magnetic core, which comprises pretreating metal magnetic powder at 1000 deg.C and H2 for 1-1.5H, sieving with 147 μm, 104 μm, 61 μm and 45 μm to obtain magnetic powder, passivating the sieved powder by chromic anhydride for surface insulation, press-forming and heat-treating to obtain magnetic powder core with magnetic permeability of 138, wherein the volume loss of the magnetic powder core is 68mW/cm under 50kHz and 50mT conditions³The method disclosed in the patent requires high-temperature pretreatment of the magnetic powder, and the process flow is complex; chinese patent with publication number CN108777205A discloses a composite powder core composed of Fe-Si-Al magnetic powder and Fe-based amorphous magnetic powder, with magnetic permeability of 140 and volume loss of 68mW/cm at 50kHz and 50mT³(ii) a The method disclosed by the patent adopts the iron-based amorphous material, so that the material cost is improved, and the loss performance is not obviously improved; the Chinese patent with publication No. CN107675074B prepares the 180-mesh crushing-method Fe-Si-Al metal magnetic powder by alloy smelting, ball milling damage and heat treatment processes; the 60 mu Fe-Si-Al powder core prepared by the metal magnetic powder disclosed by the patent has the DC resistance of about 70% under the condition of DC field intensity of 50 Oe.

The soft magnetic powder core has the advantages that the requirements for improving the performance of the soft magnetic powder core in the field of electronic power devices are met, and particularly the direct current bias performance of the soft magnetic powder core cannot meet the market requirements.

Disclosure of Invention

The invention solves the technical problem of providing a preparation method of the iron-silicon-aluminum soft magnetic powder core, and the iron-silicon-aluminum soft magnetic powder core prepared by the method greatly improves the magnetoelectric property, especially the direct current bias property of the iron-silicon-aluminum soft magnetic powder core.

In view of the above, the present application provides an sendust soft magnetic powder core, which is composed of a sendust magnetic powder and a coating layer on the surface of the magnetic powder, wherein the coating layer is composed of phosphate, silane and silicon-containing aryne resin in sequence.

The application also provides a preparation method of the Fe-Si-Al soft magnetic powder core, which comprises the following steps:

A) mixing the iron-silicon-aluminum magnetic powder with a phosphoric acid solution, heating for reaction, and drying to obtain phosphate-coated iron-silicon-aluminum powder; the Fe-Si-Al magnetic powder comprises 5.0-15.0 wt% of Si, 3.0-10.0 wt% of Al and the balance of Fe;

B) mixing the powder of the phosphate-coated Fe-Si-Al with silane hydrolysate, reacting to obtain Fe-Si-Al magnetic powder with a phosphate-silane coating layer, mixing the Fe-Si-Al magnetic powder with the phosphate-silane coating layer with silicon-containing aryne resin solution, and reacting to obtain magnetic powder with the phosphate-silane-silicon-containing aryne resin coating layer;

C) mixing the magnetic powder obtained in the step B) with a binder and a release agent, and pressing to obtain a molded magnetic core;

carrying out heat treatment on the formed magnetic core to obtain a semi-finished magnetic core;

D) and spraying a coating on the surface of the semi-finished magnetic core to obtain the metal soft magnetic powder core.

Preferably, phosphoric acid in the phosphoric acid solution accounts for 0.05-2 wt% of the sendust powder, and ethanol accounts for 2-5 wt% of the sendust powder.

Preferably, the silane hydrolysate is one or two selected from an alcohol solution of silane and an aqueous solution of silane, and the silane in the silane hydrolysate is one or more selected from gamma- (2, 3-glycidoxy) propyl trimethoxy silane, gamma-glycidoxypropyl trimethoxy silane, gamma-methacryloxypropyl trimethoxy silane, gamma-aminopropyl triethoxy silane and 3-aminopropyl triethoxy silane.

Preferably, the binder is selected from one or more of siloxane resin, phenolic resin, polyamide resin sodium silicate, lithium silicate, aluminum silicate, epoxy resin and silicone resin; the release agent is selected from one or more of zinc stearate, calcium stearate, talcum powder and mica powder.

Preferably, the silicon-containing aryne resin solution is an acetone solution of silicon-containing aryne resin, and the amount of the silicon-containing aryne resin is 1-5 wt% of the ferrum-silicon-aluminum-magnetic powder with the phosphate-silane coating layer.

Preferably, the pressing pressure is 1500-2500 MPa, the heat treatment temperature is 550-850 ℃, and the heat preservation time is 30-150 min.

Preferably, in the step C), the binder is 0.1 to 0.9 wt% of the magnetic powder, and the release agent is 0.3 to 1.0 wt% of the magnetic powder.

Preferably, in the step A), the heating temperature is 50-100 ℃.

Preferably, in the step a), the sendust magnetic powder is gas-atomized sendust magnetic powder with an average particle size of 200 meshes.

The application provides a preparation method of a Fe-Si-Al soft magnetic powder core, the prepared magnetic powder has a phosphate-silane-silicon-containing aryne resin three-layer protection structure, organic coating and inorganic coating are combined, uniform coating of the Fe-Si-Al magnetic powder is realized, the magnetoelectric property of the Fe-Si-Al soft magnetic powder core is greatly improved, particularly the DC bias property of the powder core is greatly improved, the DC bias property of the powder core under the 100Oe condition can reach 56% at most, and the performance is far higher than that of a main stream product in the market by 36%. In addition, the method disclosed by the patent does not need subsequent particle size proportioning and reducing gas protection heat treatment procedures on the raw powder, is simple and convenient to operate, and has a good market application prospect.

Drawings

FIG. 1 is a SEM image of the surface topography of a soft magnetic composite material prepared in example 1 of the present invention;

FIG. 2 is a schematic flow diagram of a magnetic powder having a phosphate-silane-silicon-containing aryne resin coating made in accordance with the present invention;

FIG. 3 is a reaction schematic diagram of the magnetic powder with a phosphate-silane-silicon-containing aryne resin coating layer prepared by the invention.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

In view of performance requirements of a soft magnetic powder core in the prior art, the application discloses a high-direct-current bias performance low-loss iron-silicon-aluminum soft magnetic powder core and a preparation method thereof, which can effectively improve the direct-current bias performance of iron-silicon-aluminum to meet the application requirements of the future market. Specifically, the embodiment of the invention discloses a preparation method of an iron-silicon-aluminum soft magnetic powder core, which comprises the following steps:

A) mixing the iron-silicon-aluminum magnetic powder with a phosphoric acid solution, heating for reaction, and drying to obtain phosphate-coated iron-silicon-aluminum powder; the Fe-Si-Al magnetic powder comprises 9.0-9.6 wt% of Si, 4.9-5.5 wt% of Al and the balance of Fe;

B) mixing the powder of the phosphate-coated Fe-Si-Al with silane hydrolysate, reacting to obtain Fe-Si-Al magnetic powder with a phosphate-silane coating layer, mixing the Fe-Si-Al magnetic powder with the phosphate-silane coating layer with silicon-containing aryne resin solution, and reacting to obtain magnetic powder with the phosphate-silane-silicon-containing aryne resin coating layer;

C) mixing the magnetic powder obtained in the step B) with a binder and a release agent, and pressing to obtain a molded magnetic core;

carrying out heat treatment on the formed magnetic core to obtain a semi-finished magnetic core;

D) and spraying a coating on the surface of the semi-finished magnetic core to obtain the metal soft magnetic powder core.

In the preparation process of the iron-silicon-aluminum soft magnetic powder core, firstly, mixing iron-silicon-aluminum magnetic powder with a phosphoric acid solution, heating for reaction, and drying to obtain powder of iron-silicon-aluminum coated with phosphate; in this process, the sendust magnetic powder is preferably a gas-atomized sendust magnetic powder having a particle size of-200 mesh, the sendust magnetic powder may have a Si content of 7.0 wt%, 8.0 wt%, 9.0 wt%, 10.0 wt%, 11.0 wt%, 12.0 wt%, 13.0 wt%, 14.0 wt%, or 15.0 wt%, and an Al content of 3.0 wt%, 4.0 wt%, 5.0 wt%, 6.0 wt%, 7.0 wt%, 8.0 wt%, 9.0 wt%, or 10.0 wt%. In order to sufficiently perform the reaction, the reaction is specifically: adding the Fe-Si-Al soft magnetic powder into a phosphoric acid solution, uniformly stirring at normal temperature to form uniform mixed slurry, transferring the mixed slurry into a water bath, heating to 50-100 ℃, continuously preserving heat and stirring to enable phosphoric acid and the powder to fully react, and after heat preservation is finished, performing magnetic separation and drying to obtain phosphate coated powder. In the phosphoric acid solution, phosphoric acid accounts for 0.05-2 wt% of the iron-silicon-aluminum-magnetic powder, and ethanol accounts for 2-5 wt% of the iron-silicon-aluminum-magnetic powder; more specifically, the phosphoric acid accounts for 0.1-1.2 wt% of the sendust powder, and the ethanol accounts for 3-4 wt% of the sendust powder. The stirring time at normal temperature is 15-25 min, the heating temperature is 60-80 ℃, and the continuous heat preservation stirring time is 20-40 min.

According to the invention, the powder of the phosphate-coated iron-silicon-aluminum is mixed with silane hydrolysate and reacted to obtain iron-silicon-aluminum magnetic powder with a phosphate-silane coating layer; in the process, the silane hydrolysate is selected from one or two of an alcohol solution of silane and an aqueous solution of silane, and the silane in the silane hydrolysate is selected from one or more of gamma- (2, 3-glycidoxy) propyl trimethoxy silane, gamma-glycidoxypropyl trimethoxy silane, gamma-methacryloxypropyl trimethoxy silane, gamma-aminopropyl triethoxy silane and 3-aminopropyl triethoxy silane. Then mixing the Fe-Si-Al magnetic powder with the phosphate-silane coating layer with a silicon-containing aryne resin solution, and reacting to obtain magnetic powder with the phosphate-silane-silicon-containing aryne resin coating layer; the specific process is shown in fig. 2 and 3. In the above process, the silicon-containing aryne resin solution is an acetone solution of silicon-containing aryne resin. The dosage of the silicon-containing aryne resin is 1-5 wt% of the ferrum-silicon-aluminum magnetic powder with the phosphate-silane coating layer; more specifically, the dosage of the silicon-containing aryne resin is 2-4 wt% of the sendust magnetic powder with the phosphate-silane coating layer. In the process of forming the phosphate-silane-silicon-containing aryne resin coating layer magnetic powder, if silicon-containing aryne resin is added firstly, the resin can be coated on the surface of the magnetic powder substrate, the reaction of phosphoric acid and the magnetic powder substrate can be prevented, and the silane enhances the binding force between the resin and the phosphate layer.

Mixing the obtained Fe-Si-Al magnetic powder with a binder and a release agent, and pressing to obtain a molded magnetic core; the binder is selected from one or more of siloxane resin, phenolic resin, polyamide resin sodium silicate, lithium silicate, aluminum silicate, epoxy resin and silicon resin; the release agent is selected from one or more of zinc stearate, calcium stearate, talcum powder and mica powder. The binder accounts for 0.1-0.9 wt% of the magnetic powder, and the release agent accounts for 0.3-1.0 wt% of the magnetic powder. The pressing pressure is 1500-2500 MPa, and more specifically, the pressing pressure is 1600-2200 MPa. After pressing, the obtained shaped magnetic core is subjected to heat treatment; the temperature of the heat treatment is 550-850 ℃, the heat preservation time is 30-150 min, more specifically, the temperature of the heat treatment is 600-700 ℃, and the heat preservation time is 60-80 min.

And finally, spraying a coating on the surface of the obtained semi-finished magnetic core to obtain the metal soft magnetic powder core, wherein the coating is an epoxy resin coating.

According to the invention, the surface of the iron-silicon-aluminum magnetic powder in the iron-silicon-aluminum soft magnetic powder core prepared by the method is sequentially coated with phosphate, silane and silicon-containing aryne resin.

The application provides a sendust soft magnetic powder core, which is characterized in that gas atomization sendust magnetic powder is preferably adopted, a phosphate-silane-silicon-containing aryne resin three-layer coating structure is creatively designed, organic coating and inorganic coating are combined, uniform coating of the magnetic powder is realized, the temperature resistance of the material can be greatly improved, and experimental results show that the sendust magnetic powder core with the effective magnetic conductivity of 88 can be prepared by the application has the direct current bias of 41% under the condition of 100Oe and the volume loss of 196.5mW/cm under 50kHz and 100mT³And the soft magnetic performance is excellent.

For further understanding of the present invention, the sendust soft magnetic powder core and the preparation method thereof provided by the present invention are described in detail below with reference to the following examples, and the scope of the present invention is not limited by the following examples.

Example 1

Selecting and using 9.0% of SiAlSiAlSi powder with the original powder granularity of-200 meshes, respectively, 6.0% of AlSi powder and the balance Fe-Si-Al powder, adding phosphoric acid accounting for 0.1% of the mass ratio of the magnetic powder and 50g of ethanol, heating in water bath for 50min at 70 ℃, performing magnetic separation to obtain phosphate-coated magnetic powder, adding the magnetic powder into silane hydrolysate, drying to obtain phosphate-silane co-coated magnetic powder, then adding the powder into silicon-containing aryne resin-acetone solution, wherein the silicon-containing aryne resin accounts for 2% of the mass ratio of the magnetic powder, and drying to obtain phosphate-silane-silicon-containing aryne resin co-coated magnetic powder; adding a proper amount of binder and release agent into the magnetic powder, and uniformly mixing to obtain magnetic powder to be molded; pressing the uniformly mixed magnetic powder to be molded into a powder core blank piece by adopting the pressing pressure of 1800MPa, wherein the powder core blank piece is an annular powder core with the outer diameter of 20.3mm, the inner diameter of 12.7mm and the height of 5mm, and preserving the heat of the powder core blank piece subjected to the pressing molding at 700 ℃ for 60min under the high vacuum condition to obtain a semi-finished magnetic powder core; finally, spraying a layer of insulating and high-temperature-resistant epoxy resin coating on the surface of the semi-finished magnetic powder core, and drying to obtain the finished metal soft magnetic powder core. Fig. 1 is an SEM photograph of the magnetic powder having the phosphate-silane-silicon-containing aryne resin coating layer prepared in this example, and it can be seen from the figure that the resin is used as the outermost layer to coat the magnetic powder substrate, the phosphate is in a micro-porous structure, the inner layer is well protected, and the silane layer increases the bonding force between the two.

The iron-silicon-aluminum magnetic powder core with the effective magnetic conductivity of 88 prepared by the method disclosed by the patent has the direct current bias of 41 percent under the condition of 100Oe and the volume loss of 196.5mW/cm under 50kHz and 100mT³And the soft magnetic performance is excellent.

Example 2

Selecting and using 9.0% of SiAlSiAlSi powder with the original powder granularity of-200 meshes, respectively, 6.0% of AlSi powder and the balance Fe-Si-Al powder, adding phosphoric acid accounting for 0.3% of the mass ratio of the magnetic powder and 50g of ethanol, heating in water bath for 50min at 70 ℃, performing magnetic separation to obtain phosphate-coated magnetic powder, adding the magnetic powder into silane hydrolysate, drying to obtain phosphate-silane co-coated magnetic powder, then adding the powder into silicon-containing aryne resin-acetone solution, wherein the silicon-containing aryne resin accounts for 2% of the mass ratio of the magnetic powder, and drying to obtain phosphate-silane-silicon-containing aryne resin co-coated magnetic powder; adding a proper amount of binder and release agent into the magnetic powder, and uniformly mixing to obtain magnetic powder to be molded; pressing the uniformly mixed magnetic powder to be molded into a powder core blank piece by adopting the pressing pressure of 1800MPa, wherein the powder core blank piece is an annular powder core with the outer diameter of 20.3mm, the inner diameter of 12.7mm and the height of 5mm, and the pressed and molded powder core blank piece is subjected to heat preservation at 700 ℃ for 60min under the high vacuum condition to obtain a semi-finished magnetic powder core; finally, spraying a layer of insulating and high-temperature-resistant epoxy resin coating on the surface of the semi-finished magnetic powder core, and drying to obtain the finished metal soft magnetic powder core.

The iron-silicon-aluminum magnetic powder core with effective magnetic conductivity 74 prepared by the method disclosed by the patent has the direct current bias of 49% under the condition of 100Oe and the volume loss of 185.6mW/cm under 50kHz and 100mT³And the soft magnetic performance is excellent.

Example 3

Selecting and using 9.0% of SiAlSiAlSi powder with the original powder granularity of-200 meshes, respectively, 6.0% of AlSiAlSi powder and the balance Fe powder, adding phosphoric acid accounting for 0.6% of the mass ratio of the magnetic powder and 50g of ethanol, heating in a water bath for 50min at 70 ℃, performing magnetic separation to obtain phosphate-coated magnetic powder, adding the magnetic powder into silane hydrolysate, drying to obtain phosphate-silane co-coated magnetic powder, then adding the powder into silicon-containing aryne resin-acetone solution, wherein the silicon-containing aryne resin accounts for 2% of the mass ratio of the magnetic powder, and drying to obtain phosphate-silane-silicon-containing aryne resin co-coated magnetic powder; adding a proper amount of binder and release agent into the magnetic powder, and uniformly mixing to obtain magnetic powder to be molded; pressing the uniformly mixed magnetic powder to be molded into a powder core blank piece by adopting the pressing pressure of 1800MPa, wherein the powder core blank piece is an annular powder core with the outer diameter of 20.3mm, the inner diameter of 12.7mm and the height of 5mm, and the pressed and molded powder core blank piece is subjected to heat preservation at 700 ℃ for 60min under the high vacuum condition to obtain a semi-finished magnetic powder core; finally, spraying a layer of insulating and high-temperature-resistant epoxy resin coating on the surface of the semi-finished magnetic powder core, and drying to obtain the finished metal soft magnetic powder core.

The direct current bias of the sendust magnetic powder core with the effective magnetic conductivity 66 prepared by the method disclosed by the patent under the condition of 100Oe is 56%, and the volume loss under 50kHz and 100mT is 169.7mW/cm³And the soft magnetic performance is excellent.

Comparative example 1

Selecting Fe-Si-Al-Si magnetic powder with the raw powder particle size of-200 meshes, wherein the mass ratio of Si is 9.0%, Al is 6.0% and Fe is the rest, adding the magnetic powder into silicon-containing aryne resin-acetone solution, the mass of the silicon-containing aryne resin is 2% of that of the magnetic powder, drying, adding the silicon-containing aryne resin into silane hydrolysate, adding phosphoric acid accounting for 0.6% of the mass ratio of the magnetic powder and 50g of ethanol, heating in water bath for 50min at 70 ℃, obtaining the magnetic powder after magnetic separation, adding a proper amount of binder and release agent into the magnetic powder, and uniformly mixing to obtain the magnetic powder to be formed; pressing the uniformly mixed magnetic powder to be molded into a powder core blank piece by adopting the pressing pressure of 1800MPa, wherein the powder core blank piece is an annular powder core with the outer diameter of 20.3mm, the inner diameter of 12.7mm and the height of 5mm, and the pressed and molded powder core blank piece is subjected to heat preservation at 700 ℃ for 60min under the high vacuum condition to obtain a semi-finished magnetic powder core; finally, spraying a layer of insulating and high-temperature-resistant epoxy resin coating on the surface of the semi-finished magnetic powder core, and drying to obtain the finished metal soft magnetic powder core.

The iron-silicon-aluminum magnetic powder core with the effective magnetic conductivity of 73 prepared by the method disclosed by the patent has the direct current bias of 31% under the condition of 100Oe and the volume loss of 298.8mW/cm under 50kHz and 100mT³。

Comparative example 2

Selecting and using 9.0% of Si9.0% and 6.0% of alloy components with the particle size of-200 meshes and the balance Fe-Si-Al-Si magnetic powder, adding the powder accounting for 2% of the mass ratio of the magnetic powder into a silicon-containing aryne resin-acetone solution, wherein the mass ratio of the silicon-containing aryne resin is 2% of the magnetic powder, and drying to obtain silicon-containing aryne resin co-coated magnetic powder; adding a proper amount of binder and release agent into the magnetic powder, and uniformly mixing to obtain magnetic powder to be molded; pressing the uniformly mixed magnetic powder to be molded into a powder core blank piece by adopting the pressing pressure of 1800MPa, wherein the powder core blank piece is an annular powder core with the outer diameter of 20.3mm, the inner diameter of 12.7mm and the height of 5mm, and the pressed and molded powder core blank piece is subjected to heat preservation at 700 ℃ for 60min under the high vacuum condition to obtain a semi-finished magnetic powder core; finally, spraying a layer of insulating and high-temperature-resistant epoxy resin coating on the surface of the semi-finished magnetic powder core, and drying to obtain the finished metal soft magnetic powder core. The direct current bias of the sendust magnetic powder core with the magnetic conductivity of 92 under the condition of 100Oe is 28 percent, and the volume loss under 50kHz and 100mT is 250.6mW/cm³。

TABLE 1 data table of performance test results of comparative example 1 and examples 1 to 4

In conclusion, the preparation method of the soft magnetic composite material provided by the invention has the advantages of simple process, mild conditions, easiness in industrialization and wide application prospect.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.