Preparation method of high-performance iron-silicon-aluminum magnetic powder core

Abstract

The application discloses a preparation method of a high-performance iron-silicon-aluminum magnetic powder core and belongs to the technical field of metal soft magnetic powder cores. In the application, a certain proportion of zinc-doped manganese oxide particles is added into traditional iron-silicon-aluminum powder, so that the comprehensive performance of the magnetic powder core is effectively improved, and the loss is reduced; hydrogen peroxide is used as a passivator, and no chromium and no phosphorus are used, so that the environment is not polluted; the hydrogen peroxide is cheap, and the raw material cost is greatly reduced; and finally, the metal magnetic powder core prepared has a uniform and complete insulating layer on the surface, is not easily affected by environmental factors, has low magnetic loss, and simultaneously maintains high magnetic permeability of the metal magnetic powder core, so that the application prospect is wide.

Description

Technical Field

[0001] This invention belongs to the field of metal soft magnetic powder core technology, specifically relating to a method for preparing a high-performance iron-silicon-aluminum magnetic powder core. Background Technology

[0002] Since the beginning of the 21st century, to meet the development demands of higher frequency, smaller size, and thinner electronic devices, magnetic powder cores have shown a trend towards higher Bs, higher μ, higher Tc, lower Ps, and lower Hc. Ferrosilicon-aluminum magnetic powder cores are a new type of soft magnetic material with magnetoelectric conversion capabilities. They are generally formed by pressing soft magnetic powder and insulating coating dielectric using powder metallurgy. They possess high saturation magnetic induction, high permeability, good DC superposition, and low loss and temperature rise under high-frequency conditions, making them suitable for high-frequency, high-power applications such as pulse transformers and flyback transformers. Due to their near-zero magnetostriction, they are suitable for line noise filters, and their internal air gap characteristics make them suitable for use as energy storage inductors, such as switching power supplies and filter inductors.

[0003] Traditional magnetic powder cores are prepared using powder metallurgy, with insulation coating, pressing, and annealing heat treatment being the key steps determining their electrical, magnetic, and mechanical properties. Insulation coating media mainly include organic, inorganic, and inorganic-organic composite insulation coating media. Organic insulating media such as epoxy resin, phenolic resin, and silicone resin have good bonding with magnetic powder, but they decompose at temperatures above 200℃. Currently, the phosphoric acid passivation method is widely used industrially to prepare phosphate insulating coatings; similarly, prolonged high-temperature treatment leads to decomposition or crystallization, causing a sharp deterioration in electrical insulation properties. Using high-melting-point oxides such as silicon dioxide, magnesium oxide, aluminum oxide, and titanium oxide as insulating media allows for high-temperature annealing to fully release the internal stress generated during pressing. However, high-melting-point oxides have poor bonding with iron-based magnetic powder, resulting in very low mechanical strength of the magnetic powder core; furthermore, the significant difference in their coefficients of thermal expansion means that temperature changes in the service environment generate substantial internal stress, leading to deterioration of magnetic properties.

[0004] For example, Chinese invention patent CN101090019 discloses a method for manufacturing a high-permeability FeSiAL magnetic powder core, including the following steps: 1) smelting FeSiAL alloy flat ingots in a vacuum induction furnace; 2) mechanically crushing the alloy flat ingots and annealing them in a hydrogen atmosphere heat treatment furnace to obtain alloy powder; 3) adding mica powder, epoxy resin adhesive, and stearic acid release agent to the alloy powder for treatment, and then molding; 4) placing the molded product in a nitrogen or argon atmosphere heat treatment furnace for heat treatment to obtain a high-permeability FeSiAL magnetic powder core. Although the FeSiAL magnetic powder core obtained by this technical solution has good performance, its shortcomings are: ① the particle size distribution of the obtained product is wide and the proportion is complex; ② the tensile strength of the product after heat treatment is low, so impregnation and curing treatments are usually required after heat treatment, which increases the production process, increases production costs, and reduces production efficiency.

[0005] Chinese patent CN102360660A discloses a ferrosilicon alloy magnetic powder core with a permeability u=50 and its preparation method. The core uses phosphoric acid as a passivating agent and phenolic resin as a binder. However, during the passivation process with phosphoric acid, the ferrosilicon alloy powder reacts with the phosphoric acid to form red iron oxide. This red substance is a semiconductor, which prevents effective separation between powder particles, resulting in high losses.

[0006] Therefore, how to optimize the traditional preparation process to significantly improve the overall performance of iron-silicon-aluminum magnetic powder cores is a technical problem that urgently needs to be solved. Summary of the Invention

[0007] This invention addresses the shortcomings of existing technologies by providing a method for preparing high-performance iron-silicon-aluminum magnetic powder cores. The prepared magnetic powder cores exhibit low power consumption and high magnetic permeability, resulting in a significant improvement in the performance of the finished product.

[0008] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a high-performance iron-silicon-aluminum magnetic powder core includes the following preparation steps:

[0010] (1) Dry the iron-silicon-aluminum alloy powder thoroughly and remove moisture;

[0011] (2) Mix the iron-silicon-aluminum powder and the composite metal oxide at a mass ratio of 20:0.1-0.3 and ball mill them for 10-20 minutes to obtain the mixed alloy powder;

[0012] (3) Passivation treatment: Immerse the mixed alloy powder in a passivation solution with a mass concentration of 0.3-0.5% for 10-20 minutes. After immersion, dry at 180-200℃ to obtain soft magnetic powder.

[0013] (4) Cold pressing: The soft magnetic powder obtained in step (3) is cold pressed into a magnetic ring using a press;

[0014] (5) High-temperature sintering: The magnetic ring is annealed in a vacuum heat treatment furnace with argon as the protective atmosphere, and then cooled to room temperature with the furnace to obtain the finished product.

[0015] Further, in step (1), the iron-silicon-aluminum alloy powder contains the following mass fractions: Fe 85%, Si 9.5%, Al 5.5%, D 50 =40-60μm.

[0016] Further, in step (2), the composite metal oxide is zinc-doped manganese oxide. The specific preparation method is as follows: 0.5 mmol Zn(NO3)2·6H2O and 1 mmol Mn(NO3)2·4H2O are dissolved in 100 mL ethylene glycol, and then 25 mL polyethylene glycol is added. The mixture is reacted at a constant temperature of 160-180℃ for 20-30 min. The product is then dispersed in an ethanol solution with a mass concentration of 50-75%, and reacted at 50-60℃ for 8-10 h. The product is then freeze-dried to obtain a hydrolysis product. The hydrolysis product is then calcined at a temperature of 400-450℃ under nitrogen protection for 1-3 h to obtain the composite metal oxide.

[0017] Furthermore, the passivation solution in step (3) is hydrogen peroxide.

[0018] Furthermore, the pressure for cold pressing in step (4) is 800-1800 MPa.

[0019] Furthermore, the sintering temperature in step (5) is 700-1000℃, and the time is 1-2h.

[0020] All raw materials used in this invention are commercially available.

[0021] Firstly, to enhance the magnetic properties of the magnetic powder core and improve the adhesion between the alloy and subsequent passivating agent, this invention prepares zinc-doped manganese oxide particles, which are extremely fine nanoparticles that effectively fill the gaps formed by coarse magnetic powder particles, thereby increasing the density of the pressed magnet. Secondly, the added elements Zn and Mn can effectively improve the DC superposition characteristics of the iron-silicon magnetic powder core and reduce magnetic loss. The resulting iron-silicon magnetic powder core has high density, a smooth surface, and good formability. Finally, Zn and Mn are relatively reactive elements, exhibiting a strong affinity for hydrogen peroxide as a passivating agent, making passivation easier and facilitating the formation of a complete coating film on the surface of the iron-silicon-aluminum powder. This results in lower magnetic loss in the obtained iron-silicon-aluminum magnetic powder core and better formability.

[0022] Beneficial effects

[0023] This invention adds a certain proportion of zinc-doped manganese oxide particles to traditional iron-silicon-aluminum powder, effectively improving the overall performance of the magnetic powder core while reducing losses. It uses hydrogen peroxide as a passivating agent, which is chromium- and phosphorus-free and does not pollute the environment. Furthermore, hydrogen peroxide is inexpensive, significantly reducing raw material costs. The resulting metal magnetic powder core has a uniform and complete insulating layer on its surface, is not easily affected by environmental factors, has low magnetic loss, and maintains high permeability, making it suitable for a wide range of market applications. Attached Figure Description

[0024] Figure 1 These are electron microscope images of the microstructure of the soft magnetic powder obtained in Example 4 and Comparative Examples 1-3 of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0026] Example 1

[0027] A method for preparing a high-performance iron-silicon-aluminum magnetic powder core includes the following preparation steps:

[0028] (1) Dry the iron-silicon-aluminum alloy powder thoroughly and remove moisture;

[0029] (2) Mix the iron-silicon-aluminum powder and the composite metal oxide at a mass ratio of 20:0.1 and ball mill them for 10 min to obtain the mixed alloy powder;

[0030] (3) Passivation treatment: The mixed alloy powder is immersed in a passivation solution with a mass concentration of 0.3% for 10 minutes. After immersion, it is dried at 180°C to obtain soft magnetic powder.

[0031] (4) Cold pressing: The soft magnetic powder obtained in step (3) is cold pressed into a magnetic ring using a press;

[0032] (5) High-temperature sintering: The magnetic ring is annealed in a vacuum heat treatment furnace, using argon as the protective atmosphere.

[0033] Then, the product is cooled to room temperature in the furnace to obtain the finished product.

[0034] Step (1) The iron-silicon-aluminum alloy powder contains the following mass fractions: Fe 85%, Si 9.5%, Al 5.5%, D 50 =40-60μm.

[0035] Step (2) The composite metal oxide is zinc-doped manganese oxide. The specific preparation method is as follows: 0.5 mmol Zn(NO3)2·6H2O and 1 mmol Mn(NO3)2·4H2O are dissolved in 100 mL ethylene glycol, and then 25 mL polyethylene glycol is added. The reaction is carried out at 160 °C for 20 min. The product is then dispersed in a 50% ethanol solution and reacted at 50 °C for 8 h. The product is then freeze-dried to obtain a hydrolysis product. The hydrolysis product is then calcined at 400 °C under nitrogen protection for 1 h to obtain the composite metal oxide.

[0036] The passivation solution in step (3) is hydrogen peroxide.

[0037] The pressure for cold pressing in step (4) is 800 MPa.

[0038] Step (5) The sintering temperature is 700℃ and the time is 1h.

[0039] Example 2

[0040] A method for preparing a high-performance iron-silicon-aluminum magnetic powder core includes the following preparation steps:

[0041] (1) Dry the iron-silicon-aluminum alloy powder thoroughly and remove moisture;

[0042] (2) Mix the iron-silicon-aluminum powder and the composite metal oxide at a mass ratio of 20:0.2 and ball mill them for 10 min to obtain the mixed alloy powder;

[0043] (3) Passivation treatment: The mixed alloy powder is immersed in a passivation solution with a mass concentration of 0.3% for 15 minutes. After immersion, it is dried at 180°C to obtain soft magnetic powder.

[0044] (4) Cold pressing: The soft magnetic powder obtained in step (3) is cold pressed into a magnetic ring using a press;

[0045] (5) High-temperature sintering: The magnetic ring is annealed in a vacuum heat treatment furnace with argon as the protective atmosphere, and then cooled to room temperature with the furnace to obtain the finished product.

[0046] Step (1) The iron-silicon-aluminum alloy powder contains the following mass fractions: Fe 85%, Si 9.5%, Al 5.5%, D 50 =40-60μm.

[0047] Step (2) The composite metal oxide is zinc-doped manganese oxide. The specific preparation method is as follows: 0.5 mmol Zn(NO3)2·6H2O and 1 mmol Mn(NO3)2·4H2O are dissolved in 100 mL ethylene glycol, and then 25 mL polyethylene glycol is added. The reaction is carried out at 160 °C for 20 min. The product is then dispersed in a 50% ethanol solution and reacted at 60 °C for 10 h. The product is then freeze-dried to obtain a hydrolysis product. The hydrolysis product is then calcined at 400 °C under nitrogen protection for 1 h to obtain the composite metal oxide.

[0048] The passivation solution in step (3) is hydrogen peroxide.

[0049] The pressure for cold pressing in step (4) is 1000 MPa.

[0050] Step (5) The sintering temperature is 800℃ and the time is 1h.

[0051] Example 3

[0052] A method for preparing a high-performance iron-silicon-aluminum magnetic powder core includes the following preparation steps:

[0053] (1) Dry the iron-silicon-aluminum alloy powder thoroughly and remove moisture;

[0054] (2) Mix the iron-silicon-aluminum powder and the composite metal oxide at a mass ratio of 20:0.2 and ball mill them for 20 minutes to obtain the mixed alloy powder.

[0055] (3) Passivation treatment: The mixed alloy powder is immersed in a passivation solution with a mass concentration of 0.5% for 15 minutes. After immersion, it is dried at 190°C to obtain soft magnetic powder.

[0056] (4) Cold pressing: The soft magnetic powder obtained in step (3) is cold pressed into a magnetic ring using a press;

[0057] (5) High-temperature sintering: The magnetic ring is annealed in a vacuum heat treatment furnace, using argon as the protective atmosphere.

[0058] Then, the product is cooled to room temperature in the furnace to obtain the finished product.

[0059] Step (1) The iron-silicon-aluminum alloy powder contains the following mass fractions: Fe 85%, Si 9.5%, Al 5.5%, D 50 =40-60μm.

[0060] Step (2) The composite metal oxide is zinc-doped manganese oxide. The specific preparation method is as follows: 0.5 mmol Zn(NO3)2·6H2O and 1 mmol Mn(NO3)2·4H2O are dissolved in 100 mL ethylene glycol, and then 25 mL polyethylene glycol is added. The reaction is carried out at 180 °C for 30 min. The product is then dispersed in a 75% ethanol solution and reacted at 50 °C for 8 h. The product is then freeze-dried to obtain a hydrolysis product. The hydrolysis product is then calcined at 400 °C under nitrogen protection for 2 h to obtain the composite metal oxide.

[0061] The passivation solution in step (3) is hydrogen peroxide.

[0062] The pressure for cold pressing in step (4) is 1200 MPa.

[0063] Step (5) The sintering temperature is 900℃ and the time is 2h.

[0064] Example 4

[0065] A method for preparing a high-performance iron-silicon-aluminum magnetic powder core includes the following preparation steps:

[0066] (1) Dry the iron-silicon-aluminum alloy powder thoroughly and remove moisture;

[0067] (2) Mix the iron-silicon-aluminum powder and the composite metal oxide at a mass ratio of 20:0.3 and ball mill them for 20 minutes to obtain the mixed alloy powder.

[0068] (3) Passivation treatment: The mixed alloy powder is immersed in a passivation solution with a mass concentration of 0.5% for 20 minutes. After immersion, it is dried at 200℃ to obtain soft magnetic powder.

[0069] (4) Cold pressing: The soft magnetic powder obtained in step (3) is cold pressed into a magnetic ring using a press;

[0070] (5) High-temperature sintering: The magnetic ring is annealed in a vacuum heat treatment furnace, using argon as the protective atmosphere.

[0071] Then, the product is cooled to room temperature in the furnace to obtain the finished product.

[0072] Step (1) The iron-silicon-aluminum alloy powder contains the following mass fractions: Fe 85%, Si 9.5%, Al 5.5%, D 50 =40-60μm.

[0073] Step (2) The composite metal oxide is zinc-doped manganese oxide. The specific preparation method is as follows: 0.5 mmol Zn(NO3)2·6H2O and 1 mmol Mn(NO3)2·4H2O are dissolved in 100 mL ethylene glycol, and then 25 mL polyethylene glycol is added. The reaction is carried out at 180 °C for 30 min. The product is then dispersed in a 75% ethanol solution and reacted at 60 °C for 10 h. The product is then freeze-dried to obtain a hydrolysis product. The hydrolysis product is then calcined at 450 °C under nitrogen protection for 3 h to obtain the composite metal oxide.

[0074] The passivation solution in step (3) is hydrogen peroxide.

[0075] The pressure for cold pressing in step (4) is 1800 MPa.

[0076] Step (5) The sintering temperature is 1000℃ and the time is 2h.

[0077] Comparative Example 1

[0078] A method for preparing a high-performance iron-silicon-aluminum magnetic powder core includes the following preparation steps:

[0079] (1) Dry the iron-silicon-aluminum alloy powder thoroughly and remove moisture;

[0080] (2) Mix the iron-silicon-aluminum powder and the composite metal oxide at a mass ratio of 20:0.3 and ball mill them for 20 minutes to obtain the mixed alloy powder.

[0081] (3) Passivation treatment: The mixed alloy powder is immersed in a passivation solution with a mass concentration of 0.5% for 20 minutes. After immersion, it is dried at 200℃ to obtain soft magnetic powder.

[0082] (4) Cold pressing: The soft magnetic powder obtained in step (3) is cold pressed into a magnetic ring using a press;

[0083] (5) High-temperature sintering: The magnetic ring is annealed in a vacuum heat treatment furnace, using argon as the protective atmosphere.

[0084] Then, the product is cooled to room temperature in the furnace to obtain the finished product.

[0085] Step (1) The iron-silicon-aluminum alloy powder contains the following mass fractions: Fe 85%, Si 9.5%, Al 5.5%, D 50 =40-60μm.

[0086] The specific preparation method of the composite metal oxide in step (2) is as follows: 1 mmol Mn(NO3)2·4H2O is dissolved in 100 mL ethylene glycol, and then 25 mL polyethylene glycol is added. The mixture is reacted at a constant temperature of 180 °C for 30 min. The product is then dispersed in a 75% ethanol solution and reacted at 60 °C for 10 h. The product is then freeze-dried to obtain a hydrolysis product. The hydrolysis product is then calcined at a temperature of 450 °C under nitrogen protection for 3 h to obtain the composite metal oxide.

[0087] The passivation solution in step (3) is hydrogen peroxide.

[0088] The pressure for cold pressing in step (4) is 1800 MPa.

[0089] Step (5) The sintering temperature is 1000℃ and the time is 2h.

[0090] In this comparative example, except that Zn is not added during the preparation of the composite metal oxide, i.e., Zn(NO3)2·6H2O is not added, all other raw materials and preparation methods are the same as in Example 4.

[0091] Comparative Example 2

[0092] A method for preparing a high-performance iron-silicon-aluminum magnetic powder core includes the following preparation steps:

[0093] (1) Dry the iron-silicon-aluminum alloy powder thoroughly and remove moisture;

[0094] (2) Mix the iron-silicon-aluminum powder and the composite metal oxide at a mass ratio of 20:0.3 and ball mill them for 20 minutes to obtain the mixed alloy powder.

[0095] (3) Passivation treatment: The mixed alloy powder is immersed in a passivation solution with a mass concentration of 0.5% for 20 minutes. After immersion, it is dried at 200℃ to obtain soft magnetic powder.

[0096] (4) Cold pressing: The soft magnetic powder obtained in step (3) is cold pressed into a magnetic ring using a press;

[0097] (5) High-temperature sintering: The magnetic ring is annealed in a vacuum heat treatment furnace, using argon as the protective atmosphere.

[0098] Then, the product is cooled to room temperature in the furnace to obtain the finished product.

[0099] Step (1) The iron-silicon-aluminum alloy powder contains the following mass fractions: Fe 85%, Si 9.5%, Al 5.5%, D 50 =40-60μm.

[0100] The specific preparation method of the composite metal oxide in step (2) is as follows: 0.5 mmol Zn(NO3)2·6H2O is dissolved in 100 mL ethylene glycol, and then 25 mL polyethylene glycol is added. The mixture is reacted at a constant temperature of 180 °C for 30 min. The product is then dispersed in a 75% ethanol solution and reacted at 60 °C for 10 h. The product is then freeze-dried to obtain a hydrolysis product. The hydrolysis product is then calcined at 450 °C under nitrogen protection for 3 h to obtain the composite metal oxide.

[0101] The passivation solution in step (3) is hydrogen peroxide.

[0102] The pressure for cold pressing in step (4) is 1800 MPa.

[0103] Step (5) The sintering temperature is 1000℃ and the time is 2h.

[0104] In this comparative example, except that Mn is not added during the preparation of the composite metal oxide, i.e., Mn(NO3)2·4H2O is not added, the other raw materials and preparation methods are the same as in Example 4.

[0105] Comparative Example 3

[0106] A method for preparing a high-performance iron-silicon-aluminum magnetic powder core includes the following preparation steps:

[0107] (1) Dry the iron-silicon-aluminum alloy powder thoroughly and remove moisture;

[0108] (2) The iron-silicon-aluminum powder was ball-milled in a ball mill for 20 minutes to obtain alloy powder;

[0109] (3) Passivation treatment: The mixed alloy powder is immersed in a passivation solution with a mass concentration of 0.5% for 20 minutes. After immersion, it is dried at 200℃ to obtain soft magnetic powder.

[0110] (4) Cold pressing: The soft magnetic powder obtained in step (3) is cold pressed into a magnetic ring using a press;

[0111] (5) High-temperature sintering: The magnetic ring is annealed in a vacuum heat treatment furnace, using argon as the protective atmosphere.

[0112] Then, the product is cooled to room temperature in the furnace to obtain the finished product.

[0113] Step (1) The iron-silicon-aluminum alloy powder contains the following mass fractions: Fe 85%, Si 9.5%, Al 5.5%, D 50 =40-60μm.

[0114] The passivation solution in step (3) is hydrogen peroxide.

[0115] The pressure for cold pressing in step (4) is 1800 MPa.

[0116] Step (5) The sintering temperature is 1000℃ and the time is 2h.

[0117] In this comparative example, except for the addition of composite metal oxides, the other raw materials and preparation methods are the same as in Example 4.

[0118] Performance testing

[0119] Performance testing was conducted in accordance with the standards GB / T3658-2008 Measurement Method of AC Magnetic Properties of Soft Magnetic Materials - Ring Specimens, GB / T13012-2008 Measurement Method of DC Magnetic Properties of Soft Magnetic Materials, SJ20966-2006 Measurement Method of Soft Magnetic Ferrite Materials, and GB / T6525-2019 Determination of Room Temperature Compressive Strength of Sintered Metallic Materials. The effective permeability μ of the powder core at 1000kHz was measured using an LCR meter. e The morphology of the soft magnetic powder was observed using a Japanese JSM-6490LV electron microscope. The magnetic loss of the magnetic powder core sample at a magnetic flux density of 100mT and a frequency range of 50kHz was measured using a SY8216B-H loss tester.

[0120] Table 1 Performance Test Results

[0121]

[0122]

[0123] As can be seen from the data in the table, the addition of composite metal oxides in the embodiments of the present invention can effectively improve the DC superposition characteristics of the magnetic powder core, reduce magnetic loss, and produce iron-silicon magnetic powder cores with high density and high effective permeability. In contrast, the performance of comparative examples 1-3, which changed the oxide doping, decreased to varying degrees. This is because zinc and manganese metals have a synergistic effect on increasing the magnetic properties of the magnetic powder core under the preparation method of the present invention; the absence of either metal weakens the effect, which is key to achieving the technical effect of the present invention. The scanning electron microscope morphology images of the soft magnetic powders also show that the magnetic core powder surface of embodiment 4 of the present invention is uniform and has a good passivation coating effect, which is also the reason for its better overall magnetic properties. In contrast, comparative examples 1-3 have rough surfaces and uniform morphology.

[0124] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-performance iron-silicon-aluminum magnetic powder core, characterized in that, The preparation steps include the following: (1) Thoroughly dry and dehumidify the iron-silicon-aluminum alloy powder; (2) Mix the iron-silicon-aluminum powder and the composite metal oxide at a mass ratio of 20:0.1-0.3, and ball mill them for 10-20 minutes to obtain the mixed alloy powder; (3) Passivation treatment: Immerse the mixed alloy powder in a passivation solution with a mass concentration of 0.3-0.5% for 10-20 minutes. After immersion, dry at 180-200℃ to obtain soft magnetic powder. (4) Cold pressing: The soft magnetic powder obtained in step (3) is cold pressed into a magnetic ring using a press; (5) High-temperature sintering: The magnetic ring is annealed in a vacuum heat treatment furnace with argon as the protective atmosphere, and then cooled to room temperature with the furnace to obtain the finished product; Step (2) The composite metal oxide is zinc-doped manganese oxide. The specific preparation method is as follows: 0.5 mmol Zn(NO3)2·6H2O and 1 mmol Mn(NO3)2·4H2O are dissolved in 100 mL ethylene glycol, and then 25 mL polyethylene glycol is added. The reaction is carried out at a constant temperature of 160-180℃ for 20-30 min. The product is then dispersed in an ethanol solution with a mass concentration of 50-75% and reacted at 50-60℃ for 8-10 h. The product is then freeze-dried to obtain a hydrolysis product. The hydrolysis product is then calcined at a temperature of 400-450℃ under nitrogen protection for 1-3 h to obtain the composite metal oxide.

2. The method for preparing the high-performance iron-silicon-aluminum magnetic powder core according to claim 1, characterized in that, Step (1) The iron-silicon-aluminum alloy powder contains the following mass fractions: Fe 85%, Si 9.5%, Al 5.5%, D 50 =40-60μm.

3. The method for preparing the high-performance iron-silicon-aluminum magnetic powder core according to claim 1, characterized in that, Step (3) The passivation solution is hydrogen peroxide.

4. The method for preparing the high-performance iron-silicon-aluminum magnetic powder core according to claim 1, characterized in that, The pressure for cold pressing in step (4) is 800-1800 MPa.

5. The method for preparing a high-performance iron-silicon-aluminum magnetic powder core according to claim 1, characterized in that, Step (5) The sintering temperature is 700-1000℃ and the time is 1-2h.

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