阅读说明：本技术 一种绝缘包覆FeSiAl复合磁粉芯及其制备方法 (Insulating coated FeSiAl composite magnetic powder core and preparation method thereof ) 是由 张雪峰 李红霞 刘先国 李忠 于 2020-11-25 设计创作，主要内容包括：本发明涉及磁性元器件技术领域,尤其涉及一种绝缘包覆FeSiAl复合磁粉芯及其制备方法,包括以下步骤：(1)将FeSiAl金属软磁粉加入到含金属空位的TiO-2前驱体溶胶中,加热搅拌均匀；(2)加TiO-2纳米粉体,得绝缘粉；(3)与粘结剂和润滑剂混合均匀,压制成型,得坯体；(4)热处理,冷却,喷涂。本发明利用TiO-2前驱体溶液与FeSiAl有较好的黏着性,可以均匀致密的包覆在磁粉芯外面,从而提高磁粉芯的电阻率,有利于提高其高频特性,降低功率损耗；通过控制TiO-2前驱体溶液的加入量,有效调控最终包覆在磁粉芯外面的TiO-2薄膜的厚度,实现对粉芯内部气隙率的调控,从而在在降低损耗的同时提高磁粉芯的磁导率。(The invention relates to the technical field of magnetic components, in particular to an insulating coated FeSiAl composite magnetic powder core and a preparation method thereof, wherein the insulating coated FeSiAl composite magnetic powder core comprises the following steps: (1) adding FeSiAl metal soft magnetic powder into TiO containing metal vacancy 2 Heating and stirring the precursor sol uniformly; (2) adding TiO 2 Obtaining insulating powder by using nano powder; (3) mixing with binder and lubricant, and press molding to obtain blank; (4) heat treatment, cooling and spraying. The invention makes use of TiO 2 The precursor solution and FeSiAl have good adhesion, and can be uniformly and compactly coated outside the magnetic powder core, so that the resistivity of the magnetic powder core is improved, the high-frequency characteristic of the magnetic powder core is improved, and the power loss is reduced; by controlling TiO 2 The adding amount of the precursor solution can effectively regulate and control the TiO finally coated outside the magnetic powder core 2 The thickness of the film realizes the regulation and control of the air gap rate in the powder core, thereby improving the magnetic conductivity of the magnetic powder core while reducing the loss.)

1. A preparation method of an insulating coated FeSiAl composite magnetic powder core is characterized by comprising the following steps:

(1) adding FeSiAl metal soft magnetic powder into the mixtureMetal vacancy TiO₂Heating and stirring the precursor sol uniformly, and drying to obtain FeSiAl metal soft magnetic powder @ TiO₂A precursor;

(2) the FeSiAl metal soft magnetic powder @ TiO obtained in the step (1)₂Adding TiO into the precursor₂Obtaining insulating powder by using nano powder; the TiO is based on the total mass of the FeSiAl metal soft magnetic powder₂The addition amount of the nano powder is 0-0.5 wt%;

(3) uniformly mixing the insulating 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 insulating coated FeSiAl composite magnetic powder core.

2. The method for preparing an insulation coated FeSiAl composite magnetic powder core as claimed in claim 1, wherein in the step (1), the TiO containing metal vacancy is₂The precursor sol comprises the following components in percentage by mass: 6-12% of absolute ethyl alcohol, 0.55-1.1% of isopropyl titanate, 3-7% of glycerol and 0.012-0.48% of hydrochloric acid.

3. The method for preparing the FeSiAl composite magnetic powder core with the insulating coating according to claim 1, wherein the heating temperature in the step (1) is 80-100%^oC, stirring for 20-40 min; the drying temperature is 90-120 DEG C^oAnd C, the time is 20-40 min.

4. The method for preparing an insulation coated FeSiAl composite magnetic powder core as claimed in claim 1, wherein in the step (2), the TiO is added₂The average particle size of the nano powder is 20-25 nm; the TiO is₂The nano powder is rutile type.

5. The method for preparing the FeSiAl composite magnetic powder core with the insulating coating according to claim 1, wherein in the step (3), the pressure for press forming is 1500-2000 MPa.

6. The preparation method of the FeSiAl composite magnetic powder core with the insulating coating as claimed in claim 1, wherein in the step (3), the addition amount of the binder is 0.5-2 wt% based on the total mass of the FeSiAl metal soft magnetic powder.

7. The method for preparing an insulated and coated FeSiAl composite magnetic powder core as claimed in claim 1, wherein in the step (3), the lubricant is added in an amount of 0.3-1.0 wt% based on the total mass of the FeSiAl metal soft magnetic powder.

8. The method for preparing the FeSiAl composite magnetic powder core with the insulation coating as claimed in claim 1, wherein in the step (3), the binder is one or more selected from epoxy resin, silicone resin, silicon dioxide, glass powder and water glass; the lubricant is selected from one or two of zinc stearate and barium stearate.

9. The method for preparing the FeSiAl composite magnetic powder core with the insulating coating according to claim 1, wherein the heat treatment temperature in the step (4) is 600-780 ℃ for 0.5-2 h.

10. An insulated coated FeSiAl composite magnetic powder core prepared by the preparation method as claimed in any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of magnetic components, in particular to an insulating coated FeSiAl composite magnetic powder core and a preparation method thereof.

Background

The miniaturization, mobility and multifunctionality of electronic components require that a magnetic core for preparing a high-performance energy storage device must have high saturation magnetic flux density, low high-frequency loss, good performance stability and the like, so that the metal magnetic powder core becomes a key material for manufacturing the electronic components, particularly high-frequency, high-current and high-power components such as a photovoltaic inverter and the like.

At present, the magnetic powder core mainly comprises an iron powder core, a molybdenum permalloy powder core, a high magnetic flux powder core, an iron-silicon magnetic powder core and an iron-silicon-aluminum magnetic powder core. The FeSiAl magnetic powder core is used as a soft magnetic material with good high-frequency performance and low cost, is widely applied to devices such as an output inductance circuit filter, a power factor corrector and the like, and has increasingly increased market demand.

The insulating coating process is the most central process in the production and manufacturing process of the FeSiAl magnetic powder core. The purpose is to form an insulating layer on the surface of the metal powder to improve the resistivity between the metal powders so as to meet the high-frequency use requirement of the metal magnetic powder core. The magnetic permeability and power loss of the FeSiAl magnetic powder core have important relations with the type, the addition amount, the forming pressure and the annealing temperature of the insulating agent. Through the insulating coating of the magnetic powder core, the resistivity of the magnetic powder core can be improved, the high-frequency characteristic of the magnetic powder core can be improved, and the power loss is reduced. However, as the insulating coating material increases, the air gap ratio inside the powder core becomes large, thereby decreasing the magnetic permeability of the magnetic powder core. Therefore, how to select a suitable cladding material to reduce its loss while obtaining high permeability becomes a challenge in the present study.

The metal powder is coated by utilizing the characteristic of good insulating property of the organic insulating coating agent, so that the metal magnetic powder core is prepared, and the metal magnetic powder core has the advantage of low power loss in an alternating current field. However, the compression resistance and heat resistance of the organic coated magnetic powder are poor, and the magnetic performance of the magnetic powder core is adversely affected by the decrease of the density of the magnetic powder core blank and the decrease of the annealing temperature heat treatment, so people have studied on the inorganic insulating coating agent.

The ceramic (metal oxide) insulating coating (silicon oxide, magnesium oxide, aluminum oxide and the like) has high heat resistance, so that the requirement of annealing heat treatment on the thermal stability of the insulating coating can be met, but the ceramic insulating coating has a magnetic dilution effect, and the silicon oxide, the magnesium oxide and the like can greatly reduce the magnetic conductivity of the magnetic powder core and deteriorate the magnetic performance of the magnetic powder core. Meanwhile, because the ceramic has hard brittleness, the insulating coating layer on the surface of the metal powder coated by the method is easy to crack in the compression molding process, so that the insulating coating is not uniform, and the eddy current loss of the magnetic core is increased.

The Chinese patent literature discloses a preparation method of a FeSiAl magnetic powder core, the application publication number of which is CN1812009A, mica powder, kaolin or a mixture of the mica powder and the kaolin are used as an insulating agent, one of epoxy resin, phenolic resin and silicon copper resin is used as a binder, zinc stearate or lithium stearate is used as a lubricant, and the magnetic powder core is obtained after annealing treatment at 500-90 ℃. The magnetic conductivity prepared by the method is good and can reach 125, but the iron loss is high and reaches 330mW/cm at 50KHz and 0.1T³。

Chinese patent literature discloses a preparation method of a metal soft magnetic powder core, the application publication number of which is CN103247403A, the invention directly 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. However, since the dispersion has poor stability and the MgO nanoparticles have poor adhesion to magnetic powder, uniform coating is difficult and the MgO nanoparticles are liable to fall off, resulting in poor insulation performance and large eddy current loss.

Chinese patent literature discloses an inorganic insulating binder for a metal soft magnetic powder core and a preparation method thereof, and the application publication number of the inorganic insulating binder is CN101089108A₂、Al₂O₃、ZrO₂The mica powder and water are mixed, and suspended particles in the hydrate solution are close to the nanometer scale, so that the composite material has double effects of insulation and bonding. The bonding effect can be strengthened in the heat treatment process, and the stability of the powder core is improved. But since the inorganic insulating binder is made of SiO₂、Al₂O₃、ZrO₂And the hydrate composition of the mica powder has stable performance, but the coating effect is not ideal, and uniform and compact coating on the FeSiAl surface is difficult to realize, so that the magnetic conductivity of the powder core is reduced.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention provides the insulating coated FeSiAl composite magnetic powder core which simultaneously realizes high magnetic conductivity and low loss of the FeSiAl metal magnetic powder core.

The invention also provides a preparation method of the insulating coated FeSiAl composite magnetic powder core, which has the advantages of low cost, simple operation and easy large-scale production.

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

a preparation method of an insulating coated FeSiAl composite magnetic powder core comprises the following steps:

(1) adding FeSiAl metal soft magnetic powder into TiO containing metal vacancy₂Heating and stirring the precursor sol uniformly, and drying to obtain FeSiAl metal soft magnetic powder @ TiO₂A precursor; the step is to coat TiO containing metal vacancy on the surface of the magnetic powder core₂The precursor sol can realize uniform and compact cladding on the magnetic powder core, so that the resistivity of the magnetic powder core is improved, and the power loss is reduced;

(2) the FeSiAl metal soft magnetic powder @ TiO obtained in the step (1)₂Adding TiO into the precursor₂Obtaining insulating powder by using nano powder; the TiO is based on the total mass of the FeSiAl metal soft magnetic powder₂The addition amount of the nano powder is 0-0.5 wt%; in this step TiO is added₂The function of the nano powder is to avoid TiO₂The coating of the precursor is not uniform;

(3) uniformly mixing the insulating 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 insulating coated FeSiAl composite magnetic powder core. In this step, TiO containing metal vacancies₂The precursor is converted into TiO containing metal vacancy in the heat treatment process₂Film(s)The semiconductor film has ferromagnetism, can effectively reduce the magnetic dilution effect, can keep the magnetic conductivity of the FeSiAl powder core while reducing the iron loss, enhances the high-frequency stability of the FeSiAl powder core, and further improves the magnetic performance of the composite material.

The innovation point of the invention is to design the nano TiO containing the metal vacancy₂The film is coated with FeSiAl metal soft magnetic composite material. On the one hand, TiO₂The solution of the precursor has better adhesion with FeSiAl, and can be uniformly and compactly coated outside the magnetic powder core, so that the resistivity of the magnetic powder core is improved, the high-frequency characteristic of the magnetic powder core is favorably improved, and the power loss is reduced. On the other hand by controlling TiO₂The adding amount of the precursor solution can effectively regulate and control the TiO finally coated outside the magnetic powder core₂The thickness of the film realizes the regulation and control of the air gap rate in the powder core, thereby improving the magnetic conductivity of the magnetic powder core while reducing the loss.

Preferably, in the step (1), the TiO containing metal vacancies₂The precursor sol comprises the following components in percentage by mass: 6-12% of absolute ethyl alcohol, 0.55-1.1% of isopropyl titanate, 3-7% of glycerol and 0.012-0.48% of hydrochloric acid. The method comprises the following specific steps: slowly dropwise adding isopropyl titanate into a mixed solution of absolute ethyl alcohol and glycerol, and then adding hydrochloric acid into the mixed solution. Magnetically stirring the solution for 30min to obtain a colorless transparent solution, namely TiO containing metal vacancy₂And (5) precursor sol.

The invention can obtain TiO containing metal vacancy by regulating and controlling the adding amount of the insulating coating material Ti source and the glycerol₂The semiconductor film has ferromagnetism, can effectively reduce the magnetic dilution effect, can keep the magnetic conductivity of the FeSiAl powder core while reducing the iron loss, enhances the high-frequency stability of the FeSiAl powder core, and further improves the magnetic performance of the composite material.

Preferably, in the step (1), the heating temperature is 80-100 ℃, and the stirring time is 20-40 min; the drying temperature is 90-120 ℃, and the drying time is 20-40 min.

Preferably, in the step (2), the TiO is₂Average particle diameter of nano-powder20-25 nm; the TiO is₂The nano powder is rutile type.

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

Preferably, in the step (3), the addition amount of the binder is 0.5-2 wt% based on the total mass of the FeSiAl metal soft magnetic powder.

Preferably, in the step (3), the lubricant is added in an amount of 0.3 to 1.0 wt% based on the total mass of the FeSiAl metal soft magnetic powder.

Preferably, in the step (3), the binder is one or more selected from epoxy resin, silicone resin, silica, glass powder and water glass.

Preferably, in the step (3), the lubricant is one or two selected from zinc stearate and barium stearate.

Preferably, in the step (4), the temperature of the heat treatment is 600-780 ℃ and the time is 0.5-2 h.

The FeSiAl metal magnetic powder core prepared by the preparation method has the characteristics of low loss, high magnetic conductivity and good bonding strength.

Therefore, the invention has the following beneficial effects:

(1) the invention makes use of TiO₂The precursor solution and FeSiAl have good adhesion, and can be uniformly and compactly coated outside the magnetic powder core, so that the resistivity of the magnetic powder core is improved, the high-frequency characteristic of the magnetic powder core is improved, and the power loss is reduced; by controlling TiO₂The adding amount of the precursor solution can effectively regulate and control the TiO finally coated outside the magnetic powder core₂The thickness of the film realizes the regulation and control of the air gap rate in the powder core, thereby improving the magnetic conductivity of the magnetic powder core while reducing the loss;

(2) the FeSiAl metal magnetic powder core prepared by the preparation method has the characteristics of low loss, high magnetic conductivity and good bonding strength.

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) Adding FeSiAl metal soft magnetic powder into TiO containing metal vacancy₂Heating and stirring the precursor sol uniformly, and drying to obtain FeSiAl metal soft magnetic powder @ TiO₂A precursor; heating at 80 deg.C, and stirring for 30 min; drying at 100 deg.C for 30 min; TiO containing metal vacancies₂The precursor sol comprises 7.5% of absolute ethyl alcohol, 0.65% of isopropyl titanate, 3% of glycerol and 0.48% of hydrochloric acid, the isopropyl titanate is slowly dripped into a mixed solution of the absolute ethyl alcohol and the glycerol, then the hydrochloric acid is added into the mixed solution, and the mixture is magnetically stirred for 30 minutes to obtain a colorless and transparent solution;

(2) uniformly mixing the insulating powder obtained in the step (1) with 1% of epoxy resin and 0.5% of zinc stearate by taking the total mass of the FeSiAl metal soft magnetic powder as a reference, and performing compression molding at 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;

(3) and (3) carrying out heat treatment on the blank obtained in the step (2) in hydrogen at the temperature of 730 ℃ for 45min, cooling and spraying to obtain the insulating coated FeSiAl composite magnetic powder core.

Example 2

(1) Adding FeSiAl metal soft magnetic powder into TiO containing metal vacancy₂Heating and stirring the precursor sol uniformly, and drying to obtain FeSiAl metal soft magnetic powder @ TiO₂A precursor; heating at 100 deg.C, and stirring for 20 min; the drying temperature is 90 ℃ and the drying time is 40 min; TiO containing metal vacancies₂The precursor sol comprises 6% of absolute ethyl alcohol, 0.55% of isopropyl titanate, 7% of glycerol and 0.024% of hydrochloric acid, the isopropyl titanate is slowly dripped into a mixed solution of the absolute ethyl alcohol and the glycerol, then the hydrochloric acid is added into the mixed solution, and the mixture is magnetically stirred for 30 minutes to obtain a colorless and transparent solution;

(2) uniformly mixing the insulating powder obtained in the step (1) with 0.1 wt% of silicone resin, 0.4 wt% of zinc stearate, 0.8 wt% of barium stearate and 0.1 wt% of barium stearate based on the total mass of the FeSiAl metal soft magnetic powder, and performing compression molding at 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;

(3) and (3) carrying out heat treatment on the blank obtained in the step (2) in nitrogen at the temperature of 600 ℃ for 2 hours, cooling and spraying to obtain the insulating coated FeSiAl composite magnetic powder core.

Example 3

(1) Adding FeSiAl metal soft magnetic powder into TiO containing metal vacancy₂Heating and stirring the precursor sol uniformly, and drying to obtain FeSiAl metal soft magnetic powder @ TiO₂A precursor; heating at 90 deg.C, and stirring for 40 min; the drying temperature is 120 ℃, and the drying time is 20 min; TiO containing metal vacancies₂The precursor sol comprises 7.5% of absolute ethyl alcohol, 0.65% of isopropyl titanate, 5% of glycerol and 0.024% of hydrochloric acid, the isopropyl titanate is slowly dripped into the mixed solution of the absolute ethyl alcohol and the glycerol, then the hydrochloric acid is added into the mixed solution, and the mixture is magnetically stirred for 30 minutes to obtain a colorless and transparent solution;

(2) the FeSiAl metal soft magnetic powder @ TiO obtained in the step (1)₂Adding rutile type TiO with the average grain diameter of 20nm into the precursor₂Obtaining insulating powder by using nano powder; the TiO is based on the total mass of the FeSiAl metal soft magnetic powder₂The addition amount of the nano powder is 0.5 wt%;

(3) uniformly mixing the insulating powder obtained in the step (2) with 0.5wt% of water glass and 0.3 wt% of zinc stearate by taking the total mass of the FeSiAl metal soft magnetic powder as a reference, and performing compression molding at 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;

(4) and (4) carrying out heat treatment on the blank obtained in the step (3) in vacuum (vacuum degree of 1Pa), cooling and spraying, wherein the heat treatment temperature is 780 ℃ and the time is 0.5h, and thus obtaining the insulating coated FeSiAl composite magnetic powder core.

Example 4

(1) Adding FeSiAl metal soft magnetic powder into TiO containing metal vacancy₂Heating and stirring the precursor sol uniformly, and drying to obtain FeSiAl metal soft magnetic powder @ TiO₂A precursor; heating at 90 deg.C, and stirring for 40 min; the drying temperature is 120 ℃, and the drying time is 20 min; TiO containing metal vacancies₂The precursor sol comprises 12% of absolute ethyl alcohol, 1.1% of isopropyl titanate, 6% of glycerol and 0.012% of hydrochloric acid, the isopropyl titanate is slowly dripped into the mixed solution of the absolute ethyl alcohol and the glycerol, then the hydrochloric acid is added into the mixed solution, and the colorless transparent solution is obtained after magnetic stirring for 30 minutes;

(2) the FeSiAl metal soft magnetic powder @ TiO obtained in the step (1)₂Adding rutile type TiO with the average grain diameter of 20nm into the precursor₂Obtaining insulating powder by using nano powder; the TiO is based on the total mass of the FeSiAl metal soft magnetic powder₂The addition amount of the nano powder is 0.3 wt%;

(3) uniformly mixing the insulating powder obtained in the step (2) with 0.5wt% of water glass and 0.3 wt% of zinc stearate by taking the total mass of the FeSiAl metal soft magnetic powder as a reference, and performing compression molding at 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;

(4) and (4) carrying out heat treatment on the blank obtained in the step (3) in vacuum (vacuum degree of 1Pa), cooling and spraying, wherein the heat treatment temperature is 780 ℃ and the time is 0.5h, and thus obtaining the insulating coated FeSiAl composite magnetic powder core.

The performance of the insulated coated FeSiAl composite magnetic powder cores prepared in examples 1-4 was examined and the results are shown in table 1:

TABLE 1 test results

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.