Magnetic powder core with high magnetic conductivity, low loss and high direct current bias and preparation method thereof

Abstract

The invention relates to a magnetic powder core with high magnetic conductivity, low loss and high direct current bias and a preparation method thereof, and the preparation method comprises the following steps: coating a complete SiO2 nano layer on the surface of soft magnetic alloy powder through a sol-gel method to obtain intermediate powder; a FeNi nanometer layer is formed on the surface layer of the middle powder through an in-situ reduction method, and insulating magnetic powder is obtained; the insulating magnetic powder is mixed with a binder and a lubricant, and then molding and heat treatment are performed in sequence to obtain the magnetic powder core with high magnetic conductivity, low loss and high direct current bias. According to the preparation method provided by the invention, the magnetically soft alloy-SiO2-FeNi structure is adopted, so that the magnetic conductivity, the loss and the direct-current bias are considered, the adverse effects of a traditional mode on the magnetic conductivity and the loss are reduced, and the magnetic core with high magnetic conductivity, low loss and good direct-current superposition performance is finally prepared.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal magnetic powder core materials, and particularly relates to a high magnetic permeability, low loss, and high DC bias magnetic powder core and a preparation method thereof. Background Art

[0002] Among many soft magnetic materials, the soft magnetic composite material (magnetic powder core) prepared by processes such as powder making, particle size ratio, insulation coating, pressing molding, and heat treatment integrates the advantages of soft magnetic alloys and soft ferrites, taking into account relatively high resistivity and saturation magnetization intensity, and is widely used as electronic components for stabilizing current and voltage. With the rapid development of emerging industries such as new energy vehicles, 5G communication, and artificial intelligence, electronic technology has shown a rapid development trend, and the miniaturization and power density of electronic devices have become an inevitable trend. In the field of magnetic powder cores, the improvement of the saturation magnetic induction intensity of soft magnetic materials helps to achieve miniaturization and power density. However, in high-frequency and high-power application scenarios, a relatively high magnetic field causes the magnetic powder core to be extremely prone to saturation and failure. Existing high-frequency and high-power application scenarios can basically be equivalent to the superposition of a DC component and an AC component. The saturation of the magnetic powder core is mainly caused by the DC component. If the DC bias performance is improved, the application range of the magnetic powder core will be greatly expanded, and the volume of the magnetic powder core can be further reduced. The method of opening an air gap in the magnetic powder core and introducing a permanent magnet into the air gap can effectively improve the DC bias performance. However, due to serious magnetic leakage at the air gap and too large losses caused by the edge effect, it not only affects the magnetic characteristics of the magnetic powder core, but also easily causes the temperature at the air gap of the magnetic powder core to be too high, resulting in the failure of the magnetic powder core.

[0003] The DC bias characteristics of magnetic powder cores are greatly related to the morphology, composition, particle size, heat treatment process, insulation coating process, etc. of soft magnetic powders. Each manufacturer uses the gas atomization method to replace the traditional crushing method, prepares spherical powders instead of irregular powders, and strengthens the demagnetizing field, which greatly improves the DC bias ability of magnetic powder cores, but still cannot meet the requirements of high-frequency high power. Chinese Patent Document CN201210389520.7 discloses "A method for preparing iron-silicon-aluminum magnetic powder with high DC bias characteristics", which improves the DC bias characteristics by adding low-hardness plastic metal powders such as iron powder and permalloy powder to iron-silicon-aluminum metal powder. However, this cannot retain the respective advantages of the composite powders. The magnetic powder cores prepared from the powders after uniform mixing cannot take into account permeability, loss, and DC bias. Chinese Patent Document CN201711342994.5 discloses "A method for preparing materials with improved DC bias characteristics and a method for preparing magnetic powder cores", in which FeSiAl magnetic powder with a mesh size of 140 and FeSiAl magnetic powder with a mesh size of 300 are ball-milled and mixed in a ratio of 1.5 to 4, and then through insulation coating, pressing, and heat treatment, magnetic powder cores are obtained, and the DC bias performance is improved by about 7%. Chinese Patent Document CN202011223981.8 discloses "A method for preparing an efficient iron-silicon-aluminum magnetic powder core and the obtained iron-silicon-aluminum magnetic powder core", in which iron-silicon-aluminum powders with different particle sizes coated with insulation are layered and filled in different proportions in a mold by in-situ composite method. The particle sizes filled are two or more of 100-400 mesh, 140-200 mesh, 400-600 mesh, and 600-1000 mesh. After pressing and heat treatment, magnetic powder cores are obtained, and the DC bias characteristics of 100 Oe are improved to 60%. The particle size ratio is essentially equivalent to using high-mesh FeSiAl magnetic powder with higher DC bias to improve the DC bias performance of low-mesh magnetic powder. From another perspective, it can also be considered that the DC bias performance of high-mesh magnetic powder is reduced, and the loss value of the magnetic powder core cannot be significantly improved. In addition, the mixing uniformity cannot be guaranteed, resulting in a poor yield of the prepared magnetic powder cores. Chinese Patent Document CN201710301201.9 discloses "An annealing method for improving the DC bias performance of iron-silicon-aluminum soft magnetic powder cores", which uses secondary annealing to heat-treat metal magnetic powder cores with a permeability of 125. Under the condition of 100 Oe, the DC bias performance is not less than 19%, and under the conditions of 50 kHz and 100 mT, the loss is not higher than 240 mW / cm 3。Chinese Patent Document CN202311857800.0 discloses "A manufacturing method of high DC bias iron-silicon-aluminum powder cores". On the basis of the conventional method of flake-breaking iron-silicon-aluminum, two steps of ball milling and recrystallization annealing are added, significantly increasing the grain boundaries and grain boundary area inside the iron-silicon-aluminum particles, greatly increasing the resistivity of the iron-silicon-aluminum powder, and improving the frequency stability and loss performance of the permeability of the powder core. At the same time, the grain size decreases, the number of grains inside the particles will increase, and the magnetic domains will also increase, making it more difficult for the powder core to be magnetized to saturation, further improving the DC bias performance of the powder core. The heat treatment method is limited to breaking iron-silicon-aluminum, and the improved DC bias performance is still much lower than that of spherical powder cores. Chinese Patent Document CN201410522934.1 discloses "A preparation method of a low-loss high-superposition iron-silicon-aluminum material with a permeability μ = 26", and through batching, phosphating, two annealing processes, adding appropriate high-temperature resistant insulating materials and coating methods, an iron-silicon-aluminum material with a permeability of 26 and a loss of 500 mW / cm under the conditions of 100 kHz / 100 mT 3 and a superposition performance of 100 Oe: 85% is achieved. Although the double-insulation coating method can greatly improve the DC superposition performance of the material, the initial permeability is also greatly reduced. It is difficult to improve the DC bias characteristics while maintaining high permeability and low loss by the above-mentioned many methods. Therefore, providing a powder core with high permeability, low loss and high DC bias characteristics and its preparation method is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects and deficiencies of the prior art and provide a powder core with high permeability, low loss and large DC bias. The insulating magnetic powder used in this powder core has a double outer layer structure, that is, it has an inner layer of SiO2 and an outer layer of FeNi. On the premise that the permeability is basically stable, the DC bias characteristics are improved synchronously and the loss is reduced, improving the high-frequency soft magnetic characteristics of the powder core.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A high-permeability, low-loss and high-DC-bias powder core, the powder core includes insulating magnetic powder; the inner core of the insulating magnetic powder is a soft magnetic alloy, and there is a double outer layer structure outside the inner core. The double outer layer structure is an inner layer of SiO2 and an outer layer of FeNi, where the thickness of the inner layer of SiO2 is 5 - 50 nm, and the thickness of the outer layer of FeNi is 5 - 50 nm.

[0007] · The present invention also provides a preparation method of a high-permeability, low-loss and high-DC-bias powder core, including the following steps:

[0008] Step (1): Coat a complete SiO2 nano-layer on the surface of soft magnetic alloy powder by sol-gel method to obtain intermediate powder;

[0009] Step (2): Form a layer of FeNi nano-layer on the surface layer of the intermediate powder obtained in step (1) by in-situ reduction method to obtain insulating magnetic powder;

[0010] Step (3): Press the insulating magnetic powder obtained in step (2) into a green body;

[0011] Step (4): Heat-treat the green body obtained in step (3) in an inert atmosphere, and finally obtain a magnetic powder core with high magnetic permeability, low loss and high DC bias after cooling.

[0012] Preferably, step (1) specifically includes the following steps:

[0013] (1.1) Dissolve 0.3 - 0.7 parts by weight of silane coupling agent in an organic aqueous solution, stir evenly, add it to 100 parts by weight of soft magnetic alloy powder, and stir evenly to obtain solution one;

[0014] (1.2) Dissolve 0.5 - 2 parts by weight of organosilane in an organic solvent, stir evenly, add the organosilane solution to solution one obtained in step (1.1), stir, filter, and obtain intermediate powder;

[0015] The said step (2) specifically includes the following steps:

[0016] (2.1) Add the intermediate powder obtained in step (1.2) to a soluble Ni salt and Fe salt solution of 0.5 - 2 parts by weight, and make Ni 2+ and Fe 2+ adsorb on the surface of the intermediate powder to obtain solution two;

[0017] (2.2) Under an inert atmosphere and in an oil bath state, add an alkaline solution of a strong reducing agent to solution two obtained in step (2.1), and obtain insulating magnetic powder after centrifugation, washing and drying;

[0018] Step (3) specifically includes the following steps:

[0019] (3.1) Dissolve 0.5 - 2 parts by weight of binder in 1.5 - 6 parts by weight of organic solvent, then add it to the insulating magnetic powder obtained in step (2.2), stir fully and dry to obtain magnetic powder;

[0020] (3.2) Add 0.5 - 1.5 parts by weight of lubricant to the magnetic powder obtained in step (3.1), stir fully and make the magnetic powder to be formed.

[0021] (3.3) Press the magnetic powder to be formed under a forming pressure.

[0022] Preferably, the silane coupling agent in step (1.1) is one or more of 3-aminopropyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane; the organic aqueous solution in step (1.1) is one or more of ethanol aqueous solution, acetone aqueous solution, and methylal aqueous solution.

[0023] Preferably, the soft magnetic alloy powder in step (1) is one or more of Fe powder, FeSi powder, FeSiAl powder, FeCo powder, and Co powder.

[0024] Preferably, the organosilane in step (1.2) is one or more of tetraethoxysilane, trimethylmethoxysilane, and dimethyldichlorosilane; the organic solvent in step (1.2) is one or more of ethanol solvent, acetone solvent, and methylal solvent.

[0025] Preferably, the soluble Ni salt in step (2.1) is one or more of NiCl2, NiSO4, Ni(NO3)2, and Ni(CH3COO)2; the soluble Fe salt is one or more of FeCl2, FeSO4, Fe(NO3)2, and Fe(CH3COO)2; the inert atmosphere in step (2.2) is N2 and Ar; the oil bath temperature is 50-90 o °C, and the oil bath time is 0.5-3 h; the strong reducing agent in step (2.2) is one or more of hydrazine hydrate, hydroxylamine, and sodium borohydride; the alkaline solution is NaOH solution.

[0026] Preferably, the binder in step (3.1) is one or more of epoxy resin, silicone resin, silica, glass powder, and water glass; the organic solvent is one or more of acetone and methylal; the lubricant in step (3.2) is one or more of zinc stearate, aluminum stearate, and barium stearate; the forming pressure in step (3.3) is 1000-2500 MPa.

[0027] Preferably, the inert atmosphere in step (4) is N2 or Ar, the annealing temperature is 500-800 o °C, and the annealing time is 0.5-3 h.

[0028] The present invention also provides a high magnetic permeability, low loss, and high DC bias magnetic powder core prepared by the described preparation method.

[0029] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0030] 1. When the FeNi nano outer layer is distributed outside the magnetic powder, due to the large magnetic permeability and small magnetic resistance, magnetic field lines are more likely to pass through, making the magnetic induction intensity on the outside the largest. As the direct current increases, the inductance gradually decreases, and the magnetic field lines gradually transfer to the inside of the magnetic powder. The maximum magnetic induction intensity appears on the inside of the magnetic powder, and the magnetic flux density will show a stepped distribution, making the magnetic induction intensity distribution more uniform. This can improve the utilization rate of the magnetic powder core, and improve the magnetic permeability and DC bias performance of the magnetic powder core.

[0031] 2. The presence of the SiO2 nano inner layer increases the resistance of the magnetic powder and can effectively reduce losses. At the same time, the SiO2 nano inner layer can promote the stepped distribution of the magnetic flux density, making the Δ magnetic induction intensity distribution more uniform, and further improving the DC bias performance of the magnetic powder core.

[0032] 3. The soft magnetic alloy-SiO2-FeNi double interface structure can enhance electron scattering, strengthen the resistance, and further reduce losses. By means of interface coupling, it is possible to balance the magnetic permeability, loss and DC bias, and promote the formation of a magnetic powder core with high magnetic permeability, low loss and high DC bias. At the same time, the double interface structure of the soft magnetic alloy can avoid the uniformity problem existing in the traditional mixing method. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a micrograph of Example 1 of this case. Figure 1 In (a) is a low-magnification transmission electron micrograph of the insulating magnetic powder in Example 1, (b) is a high-magnification transmission electron micrograph of the surface of the insulating magnetic powder in Example 1, and (c) is a high-angle annular dark-field image of the surface of the insulating magnetic powder in Example 1;

[0034] Figure 2 The relationship between the magnetic permeability and frequency of the magnetic powder core of Example 1;

[0035] Figure 3 . The DC bias characteristics of the magnetic powder core of Example 1;

[0036] Figure 4 . The core loss of the magnetic powder core of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0037] The following will further illustrate the technical solutions of the present invention through specific examples.

[0038] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the examples, unless otherwise specified, are conventional methods in the art.

[0039] Example 1

[0040] A high magnetic permeability, low loss and high DC bias magnetic powder core, wherein the insulating FeSiAl magnetic powder used in the magnetic powder core has a double outer layer structure, wherein the double outer layer structure is a SiO2 inner layer and a FeNi outer layer, wherein the SiO2 inner layer has a thickness of 5 nm and the FeNi outer layer has a thickness of 40 nm.

[0041] A method for preparing a high permeability, low loss and high DC bias magnetic powder core is as follows:

[0042] Step (1.1) dissolving 0.5 parts by weight of 3-aminopropyltrimethoxysilane in an ethanol aqueous solution, stirring evenly, adding the mixed solution to 100 parts by weight of FeSiAl powder, and stirring evenly;

[0043] Step (1.2) dissolving 0.5 parts by weight of tetraethoxysilane in acetone solvent, stirring evenly, adding the tetraethoxysilane solution to the solution obtained in step (1.1), stirring, and filtering to obtain an intermediate powder;

[0044] Step (2.1) Add the intermediate powder obtained in step (1.2) to 1 part of NiCl2 and FeCl2 solution, and after ultrasonic stirring, Ni 2+ and Fe 2+ Adsorbed on the surface of the intermediate powder;

[0045] Step (2.2) Under N2 atmosphere, add NaOH solution of hydrazine hydrate to the solution obtained in step (2.1) and o C oil bath, and then centrifugation, washing and drying to obtain insulating magnetic powder;

[0046] Step (3.1) dissolving 0.5 parts by weight of epoxy resin in 1.5 parts by weight of methylal solvent and adding the mixture to the insulating magnetic powder obtained in step (2.2), stirring the mixture thoroughly and drying the mixture;

[0047] Step (3.2): 0.5 parts by weight of zinc stearate is added to the magnetic powder obtained in step (3.1), and the mixture is stirred thoroughly to obtain the magnetic powder to be formed.

[0048] Step (3.3) presses the magnetic powder to be formed at 1500 MPa.

[0049] Step (4) The green body obtained in step (3) is heated in a N2 atmosphere for 700 o C annealing for 1h and finally cooling to obtain a magnetic powder core with a permeability of 80.8, a loss of 59.4 (50 mT / 100 kHz) and a DC bias of (62.7%, 100 Oe). Compared with the FeSiAl magnetic powder core and FeSiAl@SiO2 magnetic powder core listed in Table 1, it achieves high permeability, low loss and high DC bias characteristics.

[0050] The micrographs of this example are as follows Figure 1 As shown, other test results are as follows: The relationship between magnetic permeability and frequency is as follows Figure 2 As shown, the DC bias characteristics are as follows Figure 3 As shown, the core loss is Figure 4 shown.

[0051] Example 2

[0052] A high magnetic permeability, low loss and high DC bias magnetic powder core, wherein the insulating FeSi magnetic powder used in the magnetic powder core has a double outer layer structure, wherein the double outer layer structure is a SiO2 inner layer and a FeNi outer layer, wherein the SiO2 inner layer has a thickness of 7 nm and the FeNi outer layer has a thickness of 20 nm.

[0053] A method for preparing a high permeability, low loss and high DC bias magnetic powder core is as follows:

[0054] Step (1.1) dissolving 0.5 parts by weight of methyltriethoxysilane in an acetone aqueous solution, stirring evenly, adding the mixed solution to 100 parts by weight of FeSi powder, stirring evenly;

[0055] Step (1.2) dissolving 1 part by weight of trimethylmethoxysilane in acetone solvent, stirring evenly, adding tetraethoxysilane solution to the solution obtained in step (1.1), stirring, filtering, and obtaining an intermediate powder;

[0056] Step (2.1) Add the intermediate powder obtained in step (1.2) to 0.5 parts of NiSO4 and FeSO4 solution, and after ultrasonic stirring, Ni 2+ and Fe 2+ Adsorbed on the surface of the intermediate powder;

[0057] Step (2.2) Under N2 atmosphere, add the NaOH solution of hydroxylamine to the solution obtained in step (2.1) and continue for 2 h 60 o C oil bath, and then centrifugation, washing and drying to obtain insulating magnetic powder;

[0058] Step (3.1) dissolving 1 part by weight of silicone resin in 3 parts by weight of acetone solvent and adding the mixture to the insulating magnetic powder obtained in step (2.2), stirring the mixture thoroughly and drying the mixture;

[0059] Step (3.2): 0.5 parts by weight of aluminum stearate is added to the magnetic powder obtained in step (3.1), and the mixture is stirred thoroughly to obtain the magnetic powder to be formed.

[0060] Step (3.3) presses the magnetic powder to be formed at 1500 MPa.

[0061] Step (4): The green body obtained in step (3) is annealed in an N2 atmosphere at 700 o °C for 2 h, and finally cooled to obtain a magnetic powder core with a magnetic permeability of 79.2, a loss of 58.1 (50 mT / 100 kHz), and a DC bias of (64.5%, 100 Oe). Compared with the FeSi magnetic powder cores and FeSi@SiO2 magnetic powder cores listed in Table 1, high magnetic permeability, low loss, and high DC bias characteristics are achieved.

[0062] Example 3

[0063] A magnetic powder core with high magnetic permeability, low loss, and high DC bias, the insulating FeSiAl magnetic powder used in the magnetic powder core has a double outer layer structure, and the double outer layer structure is an inner SiO2 layer and an outer FeNi layer, where the thickness of the inner SiO2 layer is 10 nm and the thickness of the outer FeNi layer is 30 nm.

[0064] A preparation method of a magnetic powder core with high magnetic permeability, low loss, and high DC bias is as follows:

[0065] Step (1.1): Dissolve 0.5 part by weight of 3-aminopropyltrimethoxysilane in an aqueous methylal solution, stir evenly, and add the mixed solution to 100 parts by weight of FeSiAl powder, and stir evenly;

[0066] Step (1.2): Dissolve 1.5 parts by weight of dimethyldichlorosilane in an acetone solvent, stir evenly, add the tetraethoxysilane solution to the solution obtained in step (1.1), stir, and filter to obtain intermediate powder;

[0067] Step (2.1): Add the intermediate powder obtained in step (1.2) to 1 part of NiCl2 and FeSO4 solution, after ultrasonic stirring, Ni 2+ and Fe 2+ are adsorbed on the surface of the intermediate powder;

[0068] Step (2.2): Under an N2 atmosphere, add an aqueous NaOH solution of hydrazine to the solution obtained in step (2.1), and after a 1 h oil bath at 70 o °C, then centrifuge, wash, and dry to obtain insulating magnetic powder;

[0069] Step (3.1): Dissolve 1 part by weight of water glass in 3 parts by weight of acetone solvent and then add it to the insulating magnetic powder obtained in step (2.2), stir well and then dry;

[0070] Step (3.2): Add 0.5 part by weight of zinc stearate to the magnetic powder obtained in step (3.1), stir well and then make it into magnetic powder to be formed.

[0071] Step (3.3) compresses the magnetic powder to be formed at 1500 MPa.

[0072] Step (4) anneals the green body obtained in step (3) in an Ar atmosphere at 700 o °C for 1 h, and finally obtains a magnetic powder core with a magnetic permeability of 80, a loss of 54.9 (50 mT / 100 kHz), and a DC bias of (62.9%, 100 Oe). Compared with the FeSiAl magnetic powder core and FeSiAl@SiO2 magnetic powder core listed in Table 1, high magnetic permeability, low loss, and high DC bias characteristics are achieved.

[0073] The test results of the embodiments of the present invention are compared as shown in Table 1.

[0074] Table 1 Test results of magnetic powder structure parameters and electromagnetic properties of magnetic powder cores

[0075]

Claims

1. A high magnetic permeability, low loss and high DC bias magnetic powder core, characterized in that The magnetic powder core includes insulating magnetic powder; the inner core of the insulating magnetic powder is a soft magnetic alloy, and there is a double outer layer structure outside the inner core. The double outer layer structure is an SiO2 inner layer and an FeNi outer layer, where the thickness of the SiO2 inner layer is 5 - 50 nm, and the thickness of the FeNi outer layer is 5 - 50 nm.

2. A preparation method of a magnetic powder core with high magnetic permeability, low loss and high DC bias, characterized in that, It includes the following steps: Step (1): In an organic aqueous solution environment, organosilane and silane coupling agent coat a complete SiO2 nanolayer on the surface of the soft magnetic alloy powder through the sol-gel method to obtain intermediate powder. Step (2): Disperse the intermediate powder in a soluble Ni salt and Fe salt solution, add a reducing agent and heat it, and form an FeNi nanolayer on the surface layer of the intermediate powder obtained in step (1) through in-situ reduction to obtain insulating magnetic powder. Step (3): Mix the insulating magnetic powder obtained in step (2) with a binder and a lubricant, and press it into a green body. Step (4): Heat-treat the green body obtained in step (3) in an inert atmosphere, and finally cool it to obtain a magnetic powder core with high magnetic permeability, low loss, and high DC bias.

3. The preparation method according to claim 2, wherein Step (1) specifically includes the following steps: (1.1) Dissolve 0.3 - 0.7 parts by weight of silane coupling agent in an organic aqueous solution, stir evenly, add it to 100 parts by weight of soft magnetic alloy powder, and stir evenly to obtain solution one. (1.2) Dissolve 0.5 - 2 parts by weight of organosilane in an organic solvent, stir evenly, add the organosilane solution to solution one obtained in step (1.1), stir, and filter to obtain intermediate powder. The said step (2) specifically includes the following steps: (2.1) Add the intermediate powder obtained in step (1.2) to a soluble Ni salt and Fe salt solution with a weight fraction of 0.5 - 2 parts, and ultrasonically stir to adsorb Ni 2+ and Fe 2+ onto the surface of the intermediate powder to obtain Solution II; (2.2) In an inert atmosphere and an oil bath state, add an alkaline solution of a strong reducing agent to solution two obtained in step (2.1), and obtain insulating magnetic powder through centrifugation, washing, and drying. Step (3) specifically includes the following steps: (3.1) Dissolve 0.5 - 2 parts by weight of binder in 1.5 - 6 parts by weight of organic solvent, add it to the insulating magnetic powder obtained in step (2.2), stir well and then dry it to obtain magnetic powder. (3.2) Add 0.5 - 1.5 parts by weight of lubricant to the magnetic powder obtained in step (3.1), stir well to obtain magnetic powder to be formed. (3.3) Press the magnetic powder to be formed under a forming pressure.

4. The preparation method according to claim 3, characterized in that, The silane coupling agent in step (1.1) is one or more of 3-aminopropyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane. The organic aqueous solution in step (1.1) is one or more of ethanol aqueous solution, acetone aqueous solution, and methylal aqueous solution.

5. The preparation method according to claim 3, characterized in that, The soft magnetic alloy powder in step (1) is one or more of Fe powder, FeSi powder, FeSiAl powder, FeCo powder, and Co powder.

6. The preparation method according to claim 3, wherein The organosilane in step (1.2) is one or more of tetraethoxysilane, trimethylmethoxysilane, and dimethyldichlorosilane; the organic solvent in step (1.2) is one or more of ethanol solvent, acetone solvent, and methylal solvent.

7. The preparation method according to claim 3, wherein The soluble Ni salt described in step (2.1) is one or more of NiCl2, NiSO4, Ni(NO3)2, Ni(CH3COO)2; the soluble Fe salt is one or more of FeCl2, FeSO4, Fe(NO3)2, Fe(CH3COO)2; the inert atmosphere in step (2.2) is one or more of N2 and Ar; the oil bath temperature is 50~90 o °C, the oil bath time is 0.5~3 h; the strong reducing agent in step (2.2) is one or more of hydrazine hydrate, hydroxylamine, sodium borohydride; the alkaline solution is NaOH solution.

8. The preparation method according to claim 3, characterized in that, The binder described in step (3.1) is one or more of epoxy resin, silicone resin, silica, glass powder, and water glass; the organic solvent is one or more of acetone and methylal; the lubricant described in step (3.2) is one or more of zinc stearate, aluminum stearate, and barium stearate; the molding pressure described in step (3.3) is 1000-2500 MPa.

9. The preparation method according to claim 3, characterized in that, In step (4), the inert atmosphere is N2 or Ar, the annealing temperature is 500 to 800 o °C, and the annealing time is 0.5 to 3 h.

10. A high magnetic permeability, low loss, high DC bias magnetic powder core, characterized in that, Prepared by the preparation method according to any one of claims 2-9.

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