Amorphous magnetic powder core based on flexible interface and preparation method and application thereof

Abstract

The application discloses an amorphous magnetic powder core based on a flexible interface and a preparation method and application thereof. FeSi-based amorphous magnetic powder is used as raw material, a nano-nickel hydroxide flexible interface layer is constructed on the surface of the particles by using an in-situ generation method, and then the product is prepared through insulation coating, pressing forming and heat treatment. The process can precisely control the state of the coating layer, the flexible interface can buffer and disperse stress, improve the density and magnetic permeability of the magnetic powder core, and reduce the loss. The process is at normal temperature and pressure, the equipment is simple, batch production is available, and the product can be used for inductance elements in the fields of electronics, communication, new energy vehicles and the like.

Description

Technical Field

[0001] This invention belongs to the field of soft magnetic material preparation technology, specifically relating to an amorphous magnetic powder core based on a flexible interface, its preparation method and application. Specifically, a thin and uniform nickel hydroxide layer is generated on the surface of magnetic powder by in-situ generation, forming a flexible interface on the powder surface. After coating, the powder is pressed and sintered to finally obtain an amorphous magnetic powder core with high permeability and low loss. Background Technology

[0002] With the rapid development of high-frequency power electronic devices, communication power supplies, and power modules for new energy vehicles, magnetic components are continuously evolving towards higher frequencies, smaller sizes, and higher power densities. As the core magnetic material in inductors and filters, the soft magnetic properties of magnetic powder cores directly determine the energy conversion efficiency and thermal stability of the devices. Among them, amorphous alloy magnetic powder, due to its high saturation magnetic induction, low coercivity, and excellent high-frequency response characteristics, shows broad application prospects in the field of medium- and high-frequency electronic devices.

[0003] In the preparation of amorphous magnetic powder cores, the insulating layer on the surface of the powder particles not only determines the insulation capacity between particles but also affects the contact behavior and stress transfer mode between particles during pressing. Existing coatings mainly include two types: organic resins and inorganic oxides. Organic coatings have a certain deformability and can buffer local stress between particles during pressing, but their heat resistance is limited, and they are prone to thermal decomposition during subsequent annealing, leading to a decrease in insulation stability. Inorganic coatings, while having better temperature resistance, typically have relatively rigid interfaces, making them prone to local fracture under high-pressure molding conditions. This disrupts the continuity of insulation on the particle surface and creates significant residual stress in the particle contact area, thereby affecting magnetic domain rotation and causing a decrease in magnetic permeability and an increase in losses.

[0004] Studies have shown that the interfacial state between magnetic powder particles has a significant impact on the final performance of magnetic powder cores. When the interfacial layer on the particle surface is too hard, stress concentration is significant during pressing, which can easily cause local plastic instability of amorphous powder, resulting in high stress anisotropy within the magnetic particles. Conversely, when the interfacial layer is too soft, the insulation layer may lack integrity, making it difficult to maintain stable interparticle resistance. Therefore, constructing a flexible interfacial layer that combines mechanical buffering capacity and insulation stability is key to achieving a synergistic improvement in high permeability and low loss. However, existing research on constructing flexible interfaces on the surface of amorphous magnetic powder cores is still limited, especially in terms of using in-situ growth methods to achieve controllable coating thickness, uniform interface, and stability during subsequent heat treatment. Therefore, how to construct a functional layer on the surface of powder particles that combines good insulation, thermal stability, and a certain degree of interfacial flexibility to improve stress transmission behavior during pressing, reduce interfacial damage, and increase the density of magnetic powder cores has become a critical technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a method for preparing amorphous magnetic powder cores based on flexible interfaces.

[0006] This invention utilizes an in-situ generation process to prepare amorphous magnetic powder cores with high permeability and low loss, featuring a flexible nickel hydroxide interface layer structure. Specifically, an in-situ generation method is employed, using sodium hydroxide and nickel nitrate hexahydrate as reaction precursors to construct a nanoscale nickel hydroxide coating layer on the surface of amorphous magnetic powder particles. This coating layer is uniformly and densely attached to the surface of the amorphous magnetic powder particles, forming a continuous interface structure. The resulting interface layer maintains good insulation performance while possessing appropriate flexibility. This effectively reduces interparticle friction and stress concentration during subsequent pressing and heat treatment, minimizing damage to the amorphous structure and insulation layer, reducing internal residual stress, and improving the density of the magnetic powder core. Ultimately, this achieves a synergistic optimization of increased permeability and reduced magnetic loss.

[0007] The method of this invention has a relatively simple process flow, can achieve mass production according to actual needs, and also has good process controllability, making it suitable for the preparation of amorphous magnetic powder cores with different performance requirements.

[0008] Another objective of this invention is to provide a high-permeability, low-loss amorphous magnetic powder core based on a flexible interface prepared by the above-described method.

[0009] Another object of the present invention is to provide the application of the above-mentioned amorphous magnetic powder core based on flexible interface in medium and high frequency electronic devices.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a method for preparing an amorphous magnetic powder core based on a flexible interface, comprising the following steps:

[0012] (1) Add the antioxidant to a mixture of organic solvent and water, then add FeSi-based amorphous magnetic powder and dispersant, and disperse evenly to obtain a FeSi-based amorphous magnetic powder mixed solution;

[0013] (2) Add nickel salt to a mixture of organic solvent and water, then add a cationic surfactant, mix thoroughly, and obtain Ni 2+ Precursor solution;

[0014] (3) Ni 2+ The precursor solution was added dropwise to the FeSi-based amorphous magnetic powder mixed solution, and then a strong alkali salt solution was added dropwise until the system became alkaline. The reaction was stirred and the powder was separated, washed, and dried to obtain FeSi-based amorphous magnetic powder with a nano-scale nickel hydroxide coating.

[0015] (4) FeSi-based amorphous magnetic powder with a nano-sized nickel hydroxide coating layer is mixed and coated with an insulating agent, then pressed and heat-treated to obtain an amorphous magnetic powder core based on a flexible interface.

[0016] Preferably, the antioxidant in step (1) includes at least one of sodium sulfite, sodium thiosulfate, disodium ethylenediaminetetraacetate, and ascorbic acid; more preferably, it is ascorbic acid.

[0017] Preferably, the organic solvents mentioned in steps (1) and (2) include at least one of ethanol, acetone, methanol, isopropanol, acetone, and butanone.

[0018] Preferably, the volume ratio of the organic solvent to water in steps (1) and (2) is (75-85):(15-25); more preferably, it is 80:20.

[0019] Preferably, the concentration of the antioxidant in the mixed solvent in step (1) is 5 to 15 mg / L; more preferably, it is 5 to 8 mg / L.

[0020] Preferably, the amount of antioxidant used in step (1) is 0.008 to 0.015 wt% of the FeSi-based amorphous magnetic powder; more preferably, it is 0.01 wt%.

[0021] Preferably, the dispersant in step (1) includes at least one of polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polyethylene glycol (PEG), and ammonium polymethacrylate; more preferably, it is polyvinylpyrrolidone (PVP).

[0022] Preferably, the amount of dispersant used in step (1) is 0.15 to 0.25 wt% of the mass of FeSi-based amorphous magnetic powder; more preferably, it is 0.2 wt%.

[0023] Preferably, the method of uniform dispersion in step (1) includes ultrasonic dispersion and stirring; the ultrasonic dispersion time is 10 to 30 minutes; and the stirring speed is 500 to 700 rpm.

[0024] Preferably, the average particle size of the FeSi-based amorphous magnetic powder in step (1) is 15–45 μm.

[0025] Preferably, the nickel salt in step (2) includes at least one of nickel nitrate hexahydrate, nickel chloride hexahydrate, and nickel sulfate hexahydrate; more preferably, it is nickel nitrate hexahydrate.

[0026] Preferably, the Ni in step (2) 2+ In the precursor solution, Ni 2+ The concentration is 0.03–0.09 mol / L; more preferably 0.05 mol / L.

[0027] Preferably, the cationic surfactant in step (2) includes at least one of hexadecyltrimethylammonium chloride (CTAC), hexadecyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), and hexadecylpyridine chloride (CPC); more preferably, it is hexadecyltrimethylammonium chloride (CTAC).

[0028] Preferably, the amount of cationic surfactant used in step (2) is Ni 2+ The precursor solution comprises 0.035 to 0.045 wt% of its total mass; more preferably 0.04 wt%.

[0029] Preferably, the Ni in step (3) 2+ The mass ratio of nickel salt to FeSi-based amorphous magnetic powder in the precursor solution is (0.01–0.05):1.

[0030] Preferably, the Ni in step (3) 2+ The dropping rate of the precursor solution is 4–5 ml / min.

[0031] Preferably, the strong base salt in the strong base salt solution in step (3) includes at least one of sodium hydroxide, potassium hydroxide, and calcium hydroxide.

[0032] Preferably, the concentration of the strong base salt solution in step (3) is 0.08 to 0.12 mol / L.

[0033] Preferably, the dropping rate of the strong base salt solution in step (3) is 0.6 to 0.9 mL / min; more preferably, it is 0.7 to 0.8 mL / min.

[0034] Preferably, the alkalinity in step (3) refers to a pH of 9 to 11; more preferably, it is 9.8 to 10.2.

[0035] Preferably, the stirring reaction time in step (3) is 1.5 to 2.5 hours.

[0036] Preferably, the method of separating the powder in step (3) includes at least one of centrifugal separation and filtration separation; more preferably, filtration separation; the filtration separation is further preferably vacuum filtration separation.

[0037] Preferably, the washing in step (3) refers to washing with anhydrous ethanol 1 to 4 times.

[0038] Preferably, the drying temperature in step (3) is 80-100°C and the drying time is 2-4 hours.

[0039] Preferably, the insulating agent in step (4) includes at least one of silicone resin, epoxy modified resin, epoxy resin, polyamide resin, phenolic resin and polyimide resin; more preferably, it is epoxy modified resin; the epoxy modified resin can be more resistant to high temperature during sintering due to modification, which helps to make the magnetic powder core more firmly formed after sintering; the epoxy modified resin is obtained by modifying epoxy resin with silicone, acrylate, polyether, isocyanate, etc.

[0040] Preferably, the mass ratio of FeSi-based amorphous magnetic powder with nano-sized nickel hydroxide coating to insulator in step (4) is 100:(0.5-5); more preferably, it is 100:(0.5-3).

[0041] Preferably, the pressing pressure in step (4) is 1200-2000 MPa; more preferably, it is 1200-1800 MPa, and the holding time is 5-10 s.

[0042] Preferably, the temperature of the heat treatment in step (4) is 400-700℃; more preferably 480-580℃; and the time is 0.2-1.2h; more preferably 0.3-1h.

[0043] Preferably, the heat treatment in step (4) is carried out in a vacuum or protective atmosphere, wherein the protective atmosphere is at least one of nitrogen, hydrogen and rare gas atmosphere.

[0044] Preferably, the coating method in step (4) is as follows: FeSi-based amorphous magnetic powder containing a nano-sized nickel hydroxide coating layer is mixed evenly with an insulating agent and a solvent, stirred in air until the solvent evaporates, and dried to obtain an insulating coated mixed metal soft magnetic powder.

[0045] More preferably, the solvent includes at least one of xylene, acetone, anhydrous ethanol, and toluene; more preferably, it is at least one of acetone and toluene.

[0046] More preferably, the insulating agent is added to the solvent for mixing, and then the mixed metal soft magnetic powder is added for further mixing.

[0047] More preferably, the mass ratio of the solvent to the insulating agent is (1-30):1, and more preferably (10-25):1.

[0048] More preferably, the drying temperature is 50–250°C; even more preferably, it is 70–150°C, and the drying time is 2–4 hours.

[0049] Secondly, the present invention provides an amorphous magnetic powder core based on a flexible interface prepared by the above preparation method.

[0050] Thirdly, the present invention provides the application of the above-mentioned amorphous magnetic powder core based on a flexible interface in the fields of medium and high frequency power electronic devices, new generation information and communication equipment, new energy vehicles and charging infrastructure.

[0051] Preferably, the medium- and high-frequency electronic devices include inductors, filter inductors, power inductors, energy storage inductors, chokes, common-mode inductors, differential-mode inductors, transformers, high-frequency transformers, pulse transformers, reactors, magnetic amplifiers, magnetic integrated devices, DC-DC converters, AC-DC converters, on-board chargers (OBC), DC-AC inverters, magnetic components for PFC circuits, and magnetic devices for wireless charging.

[0052] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0053] (1) This invention constructs a uniform and continuous flexible interface layer on the surface of magnetic powder particles by generating nanoscale layered nickel hydroxide in situ. This interface layer can buffer and disperse mechanical and thermal stresses during pressing and heat treatment, significantly reducing the overall internal stress of the magnetic powder core. The reduction of internal stress directly leads to a reduction in eddy current loss and hysteresis loss, thereby obtaining excellent soft magnetic properties with high permeability and low loss.

[0054] (2) This invention achieves this by precisely controlling the pH value of the reaction system and the reactants (Ni 2+ With OH - By controlling key parameters such as concentration, dropping rate, reaction temperature, and stirring conditions, precise control can be achieved over the thickness, crystallinity, porosity, and morphology of the nickel hydroxide coating. The excellent process controllability makes it suitable for the preparation of amorphous magnetic powder cores with different performance requirements.

[0055] (3) The main steps of the preparation method of the present invention are liquid-phase reaction at room temperature and pressure and subsequent conventional treatment. It does not require complex and expensive equipment, the process conditions are mild and the repeatability is good. The whole process is easy to scale up and realize mass production, and it also has the flexibility to make personalized process adjustments according to specific needs, and has good industrialization prospects. Attached Figure Description

[0056] Figure 1 A schematic diagram of the process for constructing a flexible interface in situ.

[0057] Figure 2 The images show electron microscope (EM) images of the flexible insulating interface before (left) and after (right) coating with FeSiBCuNb magnetic powder in Example 1.

[0058] Figure 3 This is a schematic diagram showing the force distribution of the powder inside the magnetic powder core with and without a flexible insulating interface (left) pressed and formed according to the present invention.

[0059] Figure 4 The permeability is the FeSiBCuNb magnetic powder core with a flexible insulating interface obtained in Example 1 and the FeSiBCuNb magnetic powder core without a flexible insulating interface obtained in Comparative Example 1.

[0060] Figure 5 The magnetic losses are compared between the FeSiBCuNb magnetic powder core with a flexible insulating interface obtained in Example 1 and the FeSiBCuNb magnetic powder core without a flexible insulating interface obtained in Comparative Example 1.

[0061] Figure 6 The stress domains are those of the FeSiBCuNb magnetic powder core with a flexible insulating interface obtained in Example 1 and the FeSiBCuNb magnetic powder core without a flexible insulating interface obtained in Comparative Example 1. Detailed Implementation

[0062] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0063] Unless otherwise specified in the embodiments of this invention, the conditions shall be performed according to conventional conditions or conditions recommended by the manufacturer. All raw materials and reagents used, unless otherwise specified, are commercially available conventional products.

[0064] Example 1

[0065] (1) Dispersion treatment of FeSiBCuNb magnetic powder: 20g of FeSiBCuNb magnetic powder with an average particle size of 39μm was added to a pre-prepared low-oxidation dispersion solvent. The low-oxidation dispersion solvent was prepared by mixing anhydrous ethanol and deionized water in a volume ratio of 80:20, with a total volume of 300mL. Ascorbic acid, accounting for 0.01wt% of the mass of FeSiBCuNb, was dissolved in the solvent as an antioxidant, and the mass concentration of ascorbic acid in the low-oxidation dispersion solvent was 6.67mg / L. Polyvinylpyrrolidone (PVP), accounting for 0.2wt% of the mass of FeSiBCuNb, was added to the above mixed solvent as a dispersant. The system was ultrasonically dispersed for 8min to break up soft agglomerates, and then continuously magnetically stirred at 600rpm to maintain uniform suspension of the magnetic powder.

[0066] (2) In-situ construction of a flexible nickel hydroxide interface: Under continuous stirring, 43 mL of Ni 2+ The precursor solution was slowly added to the suspension obtained in step (1) at a dropping rate of approximately 4 mL / min. The Ni 2+ The precursor solution was prepared by dissolving nickel nitrate hexahydrate in an aqueous ethanol solution (ethanol:water = 8:2, volume ratio). 2+The solution contained 0.05 mol / L hexadecyltrimethylammonium chloride (CTAC) as a cationic surfactant, comprising 0.04 wt% of the total solution mass. Subsequently, a 0.1 mol / L NaOH solution was added dropwise to the system at a rate of 0.75 mL / min using a peristaltic pump, with the pH value of the reaction system monitored in real time. When the pH value reached 10.5, the addition of NaOH solution was stopped. Stirring continued at room temperature for 2 hours to allow nickel hydroxide to fully nucleate and grow on the surface of the FeSiBCuNb magnetic powder, forming a uniform and continuous nanoscale coating layer.

[0067] (3) Washing and drying of the coated magnetic powder: After the reaction, the product was separated by vacuum filtration. It was washed three times with anhydrous ethanol, once with a small amount of deionized water, and finally washed with anhydrous ethanol. The washed powder was placed in a vacuum drying oven at 80°C and dried for 8 hours to obtain FeSiBCuNb composite soft magnetic powder with a nickel hydroxide flexible interface layer on the surface.

[0068] (4) Coating of composite soft magnetic powder: SJ804 epoxy modified resin purchased from Yixin Chemical New Materials Co., Ltd. is added to acetone and stirred until completely dissolved. Then, composite soft magnetic powder is poured in and stirred until the acetone evaporates. The mass ratio of composite soft magnetic powder to epoxy modified resin is 100:2, and the mass ratio of epoxy resin to acetone is 1:20.

[0069] (5) Preparation of composite soft magnetic powder core: The composite soft magnetic powder was dried in vacuum at 120°C for 3 hours. The resulting powder was pressed and held at a pressure of 1200 MPa for 6 seconds to form a magnetic powder core green body. The green body was annealed in vacuum at 480°C for 0.5 hours to obtain an amorphous magnetic powder core.

[0070] The high-performance magnetic powder core with a flexible insulating interface prepared by the above method exhibits improved soft magnetic properties due to its unique flexible insulating interface. Compared with FeSiBCuNb magnetic powder cores prepared using only epoxy-modified resin as a coating agent (using the same proportions and annealing temperature), its permeability increased from 25.7 to 27.3. Furthermore, its magnetic loss, under test conditions of 50 mT and 100 kHz, decreased from 151.53 mW / cm². 3 Reduced to 122.25 mW / cm 3 This represents a decrease of 19.2%.

[0071] Example 2

[0072] (1) Dispersion treatment of FeSiB magnetic powder: 20g of FeSiB magnetic powder with an average particle size of 45μm was added to a pre-prepared low-oxidation dispersion solvent. The low-oxidation dispersion solvent was prepared by mixing anhydrous ethanol and deionized water in a volume ratio of 75:25, with a total volume of 300mL. Sodium sulfite, accounting for 0.008wt% of the FeSiB mass, was dissolved in the solvent as an antioxidant, and the mass concentration of sodium sulfite in the low-oxidation dispersion solvent was 5.3 mg / L. Polyacrylic acid (PAA), accounting for 0.15wt% of the FeSiB mass, was added to the above mixed solvent as a dispersant. The system was ultrasonically dispersed for 15min to break up soft agglomerates, and then magnetically stirred continuously at a speed of 500 rpm to maintain uniform suspension of the magnetic powder.

[0073] (2) In-situ construction of a flexible nickel hydroxide interface: Under continuous stirring, 40 mL of Ni 2+ The precursor solution was slowly added to the suspension obtained in step (1) at a dropping rate of approximately 5 mL / min. The Ni 2+ The precursor solution was prepared by dissolving nickel chloride hexahydrate in an aqueous ethanol solution (ethanol:water = 8:2, volume ratio). 2+ The solution contained 0.06 mol / L hexadecyltrimethylammonium bromide (CTAB) as a cationic surfactant at a concentration of 0.035 wt%. Subsequently, a 0.08 mol / L NaOH solution was added dropwise to the system at a rate of 0.6 mL / min using a peristaltic pump, with the pH value of the reaction system monitored in real time. When the pH value reached 9.8, the addition of NaOH solution was stopped. The mixture was stirred at room temperature for 1.5 hours to allow for sufficient heterogeneous nucleation and growth of nickel hydroxide on the FeSiB magnetic powder surface, forming a uniform nanoscale coating layer.

[0074] (3) Washing and drying of the coated magnetic powder: After the reaction, the product was centrifuged. It was washed twice with anhydrous ethanol, once with a small amount of deionized water, and finally washed with anhydrous ethanol. The washed powder was placed in a vacuum drying oven at 80°C and dried for 6 hours to obtain FeSiB composite soft magnetic powder with a nickel hydroxide flexible interface layer on the surface.

[0075] (4) Coating of composite soft magnetic powder: RSN0840 organosilicon resin purchased from Yixin Chemical New Materials Co., Ltd. is added to toluene and stirred until completely dissolved. Then, composite soft magnetic powder is poured in and stirred until the toluene evaporates. The mass ratio of composite soft magnetic powder to organosilicon resin is 100:0.5, and the mass ratio of organosilicon resin to toluene is 1:15.

[0076] (5) Preparation of composite soft magnetic powder core: The composite soft magnetic powder was dried in vacuum at 80°C for 4 hours. The resulting powder was pressed and held at a pressure of 1200MPa for 6 seconds to form a magnetic powder core green body. The green body was annealed in vacuum at 460°C for 0.5 hours to obtain an amorphous magnetic powder core.

[0077] The high-performance magnetic powder core with a flexible insulating interface prepared by the above method exhibits improved soft magnetic properties due to its unique flexible insulating interface. Compared with FeSiB magnetic powder cores prepared using only epoxy-modified resin as a coating agent (using the same proportions and annealing temperature), its permeability increased from 36.9 to 40.2. Furthermore, its magnetic loss, under test conditions of 50 mT and 100 kHz, decreased from 181.22 mW / cm². 3 Reduced to 146.37 mW / cm 3 This represents a decrease of 19.3%.

[0078] Example 3

[0079] (1) Dispersion treatment of FeSiBCu magnetic powder: 20g of FeSiBCu magnetic powder with an average particle size of 25μm was added to a pre-prepared low-oxidation dispersion solvent. The low-oxidation dispersion solvent was prepared by mixing anhydrous ethanol and deionized water in a volume ratio of 85:15, with a total volume of 300mL. Dissolved 0.015wt% of EDTA-2Na as an antioxidant in the solvent, with a mass concentration of 10 mg / L. Polyethylene glycol (PEG, molecular weight 10000) was added to the above mixed solvent as a dispersant, accounting for 0.25wt% of FeSiBCu. The system was ultrasonically dispersed for 10min to break up soft agglomerates, and then continuously magnetically stirred at 700 rpm to maintain uniform suspension of the magnetic powder.

[0080] (2) In-situ construction of a flexible nickel hydroxide interface: Under continuous stirring, 45 mL of Ni 2+ The precursor solution was slowly added to the suspension obtained in step (1) at a dropping rate of approximately 4.5 mL / min. The Ni... 2+ The precursor solution was prepared by dissolving nickel sulfate hexahydrate in an aqueous ethanol solution (ethanol:water = 8:2, volume ratio). 2+The solution contained 0.09 mol / L NaOH as a cationic surfactant, comprising 0.045 wt% of the total solution mass. Subsequently, a 0.12 mol / L NaOH solution was added dropwise to the system at a rate of 0.9 mL / min using a peristaltic pump, with the pH value of the reaction system monitored in real time. The addition of NaOH solution was stopped when the pH reached 10.2. Stirring continued at room temperature for 2.5 hours to allow for sufficient growth of nickel hydroxide on the FeSiBCu magnetic powder surface.

[0081] (3) Washing and drying of the coated magnetic powder: After the reaction, the product was separated by vacuum filtration. It was washed three times with anhydrous ethanol, once with a small amount of deionized water, and finally washed with anhydrous ethanol. The washed powder was placed in a vacuum drying oven at 100°C and dried for 10 hours to obtain FeSiBCu composite soft magnetic powder with a nickel hydroxide flexible interface layer on the surface.

[0082] (4) Coating of composite soft magnetic powder: MF-3301 epoxy resin purchased from Yixin Chemical New Materials Co., Ltd. is added to xylene and stirred until completely dissolved. Then, composite soft magnetic powder is poured in and stirred until xylene evaporates. The mass ratio of composite soft magnetic powder to epoxy resin is 100:2 and the mass ratio of epoxy resin to xylene is 1:25.

[0083] (5) Preparation of composite soft magnetic powder core: The composite soft magnetic powder was dried in vacuum at 150°C for 3 hours. The resulting powder was pressed at 1200MPa for 6 seconds to form a magnetic powder core green body. The green body was annealed in vacuum at 480°C for 0.5 hours to obtain an amorphous magnetic powder core.

[0084] The high-performance magnetic powder core with a flexible insulating interface prepared by the above method exhibits improved soft magnetic properties due to its unique flexible insulating interface. Compared with FeSiBCu magnetic powder cores prepared using only epoxy-modified resin as a coating agent (using the same proportions and annealing temperature), its permeability increased from 31.7 to 34.9. Furthermore, its magnetic loss, under test conditions of 50 mT and 100 kHz, decreased from 148.64 mW / cm². 3 Reduced to 114.48 mW / cm 3 This represents a decrease of 22.9%.

[0085] Example 4

[0086] (1) Dispersion treatment of FeSiBP magnetic powder: 20g of FeSiBP magnetic powder with an average particle size of 20μm was added to a pre-prepared low-oxidation dispersion solvent. The low-oxidation dispersion solvent was prepared by mixing anhydrous ethanol and deionized water in a volume ratio of 80:20, with a total volume of 300mL. Ascorbic acid, accounting for 0.012wt% of the FeSiBP mass, was dissolved as a composite antioxidant, and the mass concentration of ascorbic acid in the low-oxidation dispersion solvent was 8 mg / L. Polyammonium methacrylate, accounting for 0.18wt% of the FeSiBP mass, was added to the above mixed solvent as a dispersant. The system was ultrasonically dispersed for 15min to break up soft agglomerates, and then continuously magnetically stirred at a speed of 550 rpm to maintain uniform suspension of the magnetic powder.

[0087] (2) In-situ construction of a flexible nickel hydroxide interface: Under continuous stirring, 43 mL of Ni 2+ The precursor solution was slowly added to the suspension obtained in step (1) at a dropping rate of approximately 4 mL / min. The Ni 2+ The precursor solution was prepared by dissolving nickel nitrate hexahydrate in an aqueous ethanol solution (ethanol:water = 8:2, volume ratio). 2+ The solution contained 0.07 mol / L hexadecyltrimethylammonium chloride (CTAC) as a cationic surfactant, comprising 0.038 wt% of the total solution mass. Subsequently, a 0.09 mol / L NaOH solution was added dropwise to the system at a rate of 0.7 mL / min using a peristaltic pump, with the pH value of the reaction system monitored in real time. The addition of NaOH solution was stopped when the pH reached 10.0. Stirring continued at room temperature for 2 hours to allow for sufficient heterogeneous nucleation and growth of nickel hydroxide on the FeSiBP magnetic powder surface.

[0088] (3) Washing and drying of the coated magnetic powder: After the reaction, the product was separated by vacuum filtration. It was washed three times with anhydrous ethanol, once with a small amount of deionized water, and finally washed with anhydrous ethanol. The washed powder was placed in a vacuum drying oven at 90°C and dried for 3 hours to obtain FeSiBP composite soft magnetic powder with a nickel hydroxide flexible interface layer on the surface.

[0089] (4) Coating of composite soft magnetic powder: SJ804 epoxy modified resin purchased from Yixin Chemical New Materials Co., Ltd. was added to a mixed solvent of toluene and acetone (volume ratio 1:1) and stirred until completely dissolved. Then, composite soft magnetic powder was poured in and stirred until the solvent evaporated. The mass ratio of composite soft magnetic powder to epoxy modified resin was 100:1 and the mass ratio of epoxy modified resin to mixed solvent was 1:18.

[0090] (5) Preparation of composite soft magnetic powder core: The composite soft magnetic powder was dried in vacuum at 100°C for 3 hours. The resulting powder was pressed and held at a pressure of 1500 MPa for 6 seconds to form a magnetic powder core green body. The green body was annealed in vacuum at 470°C for 0.5 hours to obtain an amorphous magnetic powder core.

[0091] The high-performance magnetic powder core with a flexible insulating interface prepared by the above method exhibits improved soft magnetic properties due to its unique flexible insulating interface. Compared with FeSiBP magnetic powder cores prepared using only epoxy-modified resin as a coating agent (using the same proportions and annealing temperature), its permeability increased from 36.8 to 39.5. Furthermore, its magnetic loss, under test conditions of 50 mT and 100 kHz, decreased from 139.86 mW / cm². 3 Reduced to 104.33 mW / cm 3 This represents a decrease of 25.1%.

[0092] Example 5

[0093] (1) Dispersion treatment of FeSiB magnetic powder: 20g of FeSiB magnetic powder with an average particle size of 16μm was added to a pre-prepared low-oxidation dispersion solvent. The low-oxidation dispersion solvent was prepared by mixing anhydrous ethanol and deionized water in a volume ratio of 78:22, with a total volume of 300mL. Ascorbic acid, accounting for 0.01wt% of the mass of FeSiB, was dissolved in the solvent as an antioxidant, and the mass concentration of ascorbic acid in the low-oxidation dispersion solvent was 6.67 mg / L. Polyvinylpyrrolidone (PVP), accounting for 0.22wt% of the mass of FeSiB, was added to the above mixed solvent as a dispersant. The system was ultrasonically dispersed for 15min to break up soft agglomerates, and then continuously magnetically stirred at a speed of 650rpm to maintain the uniform suspension of the magnetic powder.

[0094] (2) In-situ construction of a flexible nickel hydroxide interface: Under continuous stirring, 44 mL of Ni 2+ The precursor solution was slowly added to the suspension obtained in step (1) at a dropping rate of approximately 4.8 mL / min. The Ni... 2+ The precursor solution was prepared by dissolving nickel nitrate hexahydrate in an aqueous ethanol solution (ethanol:water = 8:2, volume ratio). 2+ The solution contained 0.08 mol / L NaOH at a concentration of 0.042 wt% as a cationic surfactant, specifically cetylpyridine chloride (CPC). Subsequently, a 0.11 mol / L NaOH solution was added dropwise to the system at a rate of 0.85 mL / min using a peristaltic pump, with the pH of the reaction system monitored in real time. The addition of NaOH solution was stopped when the pH reached 10.8. Stirring continued at room temperature for 2.2 hours to allow for sufficient growth of nickel hydroxide on the FeSiB magnetic powder surface.

[0095] (3) Washing and drying of the coated magnetic powder: After the reaction, the product was centrifuged. It was washed twice with anhydrous ethanol, once with a small amount of deionized water, and finally washed with anhydrous ethanol. The washed powder was placed in a vacuum drying oven at 85°C and dried for 3 hours to obtain FeSiB composite soft magnetic powder with a nickel hydroxide flexible interface layer on the surface.

[0096] (4) Coating of composite soft magnetic powder: VT8140 polyamide resin purchased from Yongxin Chemical Materials Co., Ltd. is added to anhydrous ethanol and stirred until completely dissolved. Then, composite soft magnetic powder is poured in and stirred until the ethanol evaporates. The mass ratio of composite soft magnetic powder to polyamide resin is 100:2, and the mass ratio of polyamide resin to anhydrous ethanol is 1:12.

[0097] (5) Preparation of composite soft magnetic powder core: The composite soft magnetic powder was dried in vacuum at 130°C for 3 hours. The resulting powder was pressed and held at a pressure of 1400 MPa for 6 seconds to form a magnetic powder core green body. The green body was annealed in vacuum at 450°C for 0.5 hours to obtain an amorphous magnetic powder core.

[0098] The high-performance magnetic powder core with a flexible insulating interface prepared by the above method exhibits improved soft magnetic properties due to its unique flexible insulating interface. Compared with FeSiB magnetic powder cores prepared using only epoxy-modified resin as a coating agent (using the same proportions and annealing temperature), its permeability increased from 29.8 to 33.5. Furthermore, its magnetic loss, under test conditions of 50 mT and 100 kHz, decreased from 134.92 mW / cm². 3 Reduced to 101.65 mW / cm 3 This represents a decrease of 24.6%.

[0099] Example 6

[0100] (1) Dispersion treatment of FeSiB magnetic powder: 14g of FeSiB magnetic powder with an average particle size of 45μm and 6g of FeSiB magnetic powder with an average particle size of 16μm were added to a pre-prepared low-oxidation dispersion solvent. The low-oxidation dispersion solvent was prepared by mixing anhydrous ethanol and deionized water in a volume ratio of 82:18, with a total volume of 300mL. Ascorbic acid, accounting for 0.01wt% of the FeSiB mass, was dissolved in the solvent as an antioxidant, and the mass concentration of ascorbic acid in the low-oxidation dispersion solvent was 6.67 mg / L. PVP, accounting for 0.2wt% of the FeSiB mass, and PAA, accounting for 0.05wt% of the FeSiB mass, were added to the above mixed solvent as a composite dispersant. The system was ultrasonically dispersed for 15min to break up soft agglomerates, and then continuously magnetically stirred at a speed of 580 rpm to maintain the uniform suspension of the magnetic powder.

[0101] (2) In-situ construction of a flexible nickel hydroxide interface: Under continuous stirring, 41 mL of Ni 2+ The precursor solution was slowly added to the suspension obtained in step (1) at a dropping rate of approximately 4.2 mL / min. The Ni... 2+ The precursor solution was prepared by dissolving nickel nitrate hexahydrate and nickel chloride hexahydrate (mass ratio 4:1) in an aqueous ethanol solution (ethanol:water = 8:2, volume ratio). 2+ The solution contained 0.065 mol / L NaOH as a cationic surfactant, comprising 0.036 wt% of the total solution mass. Subsequently, a 0.095 mol / L NaOH solution was added dropwise to the system at a rate of 0.65 mL / min using a peristaltic pump, with the pH value of the reaction system monitored in real time. When the pH reached 9.5, the addition of NaOH solution was stopped. Stirring continued at room temperature for 1.8 hours to allow for sufficient heterogeneous nucleation of nickel hydroxide on the FeSiB magnetic powder surface.

[0102] (3) Washing and drying of the coated magnetic powder: After the reaction, the product was separated by vacuum filtration. It was washed three times with anhydrous ethanol, once with a small amount of deionized water, and finally washed with anhydrous ethanol. The washed powder was placed in a vacuum drying oven at 95°C and dried for 3 hours to obtain FeSiB composite soft magnetic powder with a nickel hydroxide flexible interface layer on the surface.

[0103] (4) Coating of composite soft magnetic powder: DEN483 phenolic resin purchased from Yixin Chemical New Materials Co., Ltd. is added to acetone and stirred until completely dissolved. Then, composite soft magnetic powder is poured in and stirred until the acetone evaporates. The mass ratio of composite soft magnetic powder to phenolic resin is 100:2.5, and the mass ratio of phenolic resin to acetone is 1:22.

[0104] (5) Preparation of composite soft magnetic powder core: The composite soft magnetic powder was dried in vacuum at 120°C for 3 hours. The resulting powder was pressed and held at a pressure of 1500 MPa for 6 seconds to form a magnetic powder core green body. The green body was annealed in vacuum at 480°C for 0.5 hours to obtain an amorphous magnetic powder core.

[0105] The high-performance magnetic powder core with a flexible insulating interface prepared by the above method exhibits improved soft magnetic properties due to its unique flexible insulating interface. Compared with FeSiB magnetic powder cores prepared using only epoxy-modified resin as a coating agent (using the same proportions and annealing temperature), its permeability increased from 42.7 to 46.4. Furthermore, its magnetic loss, under test conditions of 50 mT and 100 kHz, decreased from 128.77 mW / cm². 3 Reduced to 94.83 mW / cm 3 This represents a decrease of 26.6%.

[0106] Example 7

[0107] (1) Dispersion treatment of FeSiBP magnetic powder: 20g of FeSiBP magnetic powder with an average particle size of 20μm was added to a pre-prepared low-oxidation dispersion solvent. The low-oxidation dispersion solvent was prepared by mixing anhydrous ethanol and deionized water in a volume ratio of 80:20, with a total volume of 300mL. Ascorbic acid, accounting for 0.01wt% of the FeSiBP mass, was dissolved in the solvent as an antioxidant, and the mass concentration of ascorbic acid in the low-oxidation dispersion solvent was 6.67 mg / L. Polyammonium methacrylate, accounting for 0.18wt% of the FeSiBP mass, was added to the above mixed solvent as a dispersant. The system was ultrasonically dispersed for 15min to break up soft agglomerates, and then magnetically stirred continuously at a speed of 550 rpm to maintain uniform suspension of the magnetic powder.

[0108] (2) In-situ construction of a flexible nickel hydroxide interface: Under continuous stirring, 43 mL of Ni 2+ The precursor solution was slowly added to the suspension obtained in step (1) at a dropping rate of approximately 4 mL / min. The Ni 2+ The precursor solution was prepared by dissolving nickel nitrate hexahydrate in an aqueous ethanol solution (ethanol:water = 8:2, volume ratio). 2+ The solution contained 0.07 mol / L hexadecyltrimethylammonium chloride (CTAC) as a cationic surfactant, comprising 0.038 wt% of the total solution mass. Subsequently, a 0.09 mol / L NaOH solution was added dropwise to the system at a rate of 0.7 mL / min using a peristaltic pump, with the pH value of the reaction system monitored in real time. The addition of NaOH solution was stopped when the pH reached 10.0. Stirring continued at room temperature for 2 hours to allow for sufficient heterogeneous nucleation and growth of nickel hydroxide on the FeSiBP magnetic powder surface.

[0109] (3) Washing and drying of the coated magnetic powder: After the reaction, the product was separated by vacuum filtration. It was washed three times with anhydrous ethanol, once with a small amount of deionized water, and finally washed with anhydrous ethanol. The washed powder was placed in a vacuum drying oven at 90°C and dried for 3 hours to obtain FeSiBP composite soft magnetic powder with a nickel hydroxide flexible interface layer on the surface.

[0110] (4) Coating of composite soft magnetic powder: SJ804 epoxy modified resin purchased from Yixin Chemical New Materials Co., Ltd. was added to a mixed solvent of toluene and acetone (volume ratio 1:1) and stirred until completely dissolved. Then, composite soft magnetic powder was poured in and stirred until the solvent evaporated. The mass ratio of composite soft magnetic powder to epoxy modified resin was 100:1 and the mass ratio of epoxy modified resin to mixed solvent was 1:18.

[0111] (5) Preparation of composite soft magnetic powder core: The composite soft magnetic powder was dried in vacuum at 100°C for 3 hours. The resulting powder was pressed and held at a pressure of 1500 MPa for 6 seconds to form a magnetic powder core green body. The green body was annealed in vacuum at 470°C for 0.5 hours to obtain an amorphous magnetic powder core.

[0112] The high-performance magnetic powder core with a flexible insulating interface prepared by the above method exhibits improved soft magnetic properties due to its unique flexible insulating interface. Compared with FeSiBP magnetic powder cores prepared by composite coating of nickel oxide and epoxy modified resin (using the same ratio and annealing temperature), its permeability increased from 36.2 to 39.5. Furthermore, its magnetic loss, under test conditions of 50 mT and 100 kHz, decreased from 131.74 mW / cm². 3 Reduced to 104.33 mW / cm 3 This represents a decrease of 20.9%.

[0113] Example 8

[0114] (1) Dispersion treatment of FeSiB magnetic powder: 20g of FeSiB magnetic powder with an average particle size of 16μm was added to a pre-prepared low-oxidation dispersion solvent. The low-oxidation dispersion solvent was prepared by mixing anhydrous ethanol and deionized water in a volume ratio of 78:22, with a total volume of 300mL. Ascorbic acid, accounting for 0.01wt% of the FeSiB mass, was dissolved in the solvent as an antioxidant, and the mass concentration of ascorbic acid in the low-oxidation dispersion solvent was 6.67 mg / L. Polyvinylpyrrolidone (PVP), accounting for 0.22wt% of the FeSiB mass, was added to the suspension as a dispersant. The system was ultrasonically dispersed for 15min to break up soft agglomerates, and then continuously magnetically stirred at a speed of 650 rpm to maintain the uniform suspension of the magnetic powder.

[0115] (2) In-situ construction of a flexible nickel hydroxide interface: Under continuous stirring, 44 mL of Ni 2+ The precursor solution was slowly added to the suspension obtained in step (1) at a dropping rate of approximately 4.8 mL / min. The Ni... 2+ The precursor solution was prepared by dissolving nickel nitrate hexahydrate in an aqueous ethanol solution (ethanol:water = 8:2, volume ratio). 2+ The solution contained 0.08 mol / L NaOH at a concentration of 0.042 wt% as a cationic surfactant, specifically cetylpyridine chloride (CPC). Subsequently, a 0.11 mol / L NaOH solution was added dropwise to the system at a rate of 0.85 mL / min using a peristaltic pump, with the pH of the reaction system monitored in real time. The addition of NaOH solution was stopped when the pH reached 10.8. Stirring continued at room temperature for 2.2 hours to allow for sufficient growth of nickel hydroxide on the FeSiB magnetic powder surface.

[0116] (3) Washing and drying of the coated magnetic powder: After the reaction, the product was centrifuged. It was washed twice with anhydrous ethanol, once with a small amount of deionized water, and finally washed with anhydrous ethanol. The washed powder was placed in a vacuum drying oven at 85°C and dried for 3 hours to obtain FeSiB composite soft magnetic powder with a nickel hydroxide flexible interface layer on the surface.

[0117] (4) Coating of composite soft magnetic powder: VT8140 polyamide resin purchased from Yongxin Chemical Materials Co., Ltd. is added to anhydrous ethanol and stirred until completely dissolved. Then, composite soft magnetic powder is poured in and stirred until the ethanol evaporates. The mass ratio of composite soft magnetic powder to polyamide resin is 100:2, and the mass ratio of polyamide resin to anhydrous ethanol is 1:12.

[0118] (5) Preparation of composite soft magnetic powder core: The composite soft magnetic powder was dried in vacuum at 130°C for 3 hours. The resulting powder was pressed and held at a pressure of 1400 MPa for 6 seconds to form a magnetic powder core green body. The green body was annealed in vacuum at 450°C for 0.5 hours to obtain an amorphous magnetic powder core.

[0119] The high-performance magnetic powder core with a flexible insulating interface prepared by the above method exhibits improved soft magnetic properties due to its unique flexible insulating interface. Compared with FeSiBP magnetic powder cores prepared by composite coating of nickel oxide and epoxy modified resin (using the same ratio and annealing temperature), its permeability increased from 28.6 to 33.5. Furthermore, its magnetic loss, under test conditions of 50 mT and 100 kHz, decreased from 126.57 mW / cm². 3 Reduced to 101.65 mW / cm 3 This represents a decrease of 19.7%.

[0120] Comparative Examples 1-6 are compared with Examples 1-6 respectively. The specific preparation methods of the soft magnetic powder cores are the same, the only difference is that the step of preparing the flexible insulating interface in the examples is omitted. That is, in Comparative Example 1, FeSiBCuNb magnetic powder with an average particle size of 39μm is directly coated with epoxy modified resin in step (4), dried at 120°C in vacuum for 3 hours, pressed at 1200MPa for 6 seconds, and annealed at 480°C in vacuum for 0.5 hours; in Comparative Example 2, FeSiB magnetic powder with an average particle size of 45μm is coated with silicone resin in step (4), dried at 80°C in vacuum for 4 hours, pressed at 1200MPa for 6 seconds, and annealed at 460°C in vacuum for 0.5 hours; in Comparative Example 3, FeSiBCu magnetic powder with an average particle size of 25μm is directly coated with epoxy resin in step (4), dried at 150°C in vacuum for 3 hours, and annealed at 1200MPa for 6 seconds, and annealed at 460°C in vacuum for 0.5 hours. The sample was held at 200 MPa for 6 seconds and then annealed under vacuum at 480°C for 0.5 h. Comparative Example 4 directly used FeSiBP magnetic powder with an average particle size of 20 μm, coated with epoxy modified resin in step (4), dried under vacuum at 100°C for 3 h, held at 1500 MPa for 6 seconds, and then annealed under vacuum at 470°C for 0.5 h. Comparative Example 5 directly used FeSiB magnetic powder with an average particle size of 16 μm, coated with polyamide in step (4). After resin coating, it was dried in vacuum at 130°C for 3 hours, held under pressure of 1400MPa for 6 seconds, and annealed in vacuum at 450°C for 0.5 hours. Comparative Example 6 directly used two FeSiB magnetic powders with different average particle sizes (45μm and 16μm) to be coated with phenolic resin in step (4), dried in vacuum at 120°C for 3 hours, held under pressure of 1500MPa for 6 seconds, and annealed in vacuum at 480°C for 0.5 hours.

[0121] Comparative Examples 7-8 and Examples 7-8 are compared respectively. The specific preparation methods of the soft magnetic powder core are the same. The difference is that the step of preparing the flexible insulating interface in the examples is omitted, and nickel oxide is added during the resin dissolution process. The mass ratio of soft magnetic powder to nickel oxide is 100:1. That is, in Comparative Example 7, FeSiBP magnetic powder with an average particle size of 20μm and nano-sized nickel oxide accounting for 0.01wt% of the FeSiBP magnetic powder are uniformly mixed by centrifugal mixing. The resulting mixed powder is coated with epoxy modified resin in step (4). The mixture was dried in vacuum at 100°C for 3 hours, pressed at 1500MPa for 6 seconds, and annealed in vacuum at 470°C for 0.5 hours. In Comparative Example 8, FeSiB magnetic powder with an average particle size of 16μm and nano-sized nickel oxide accounting for 0.01wt% of the FeSiB magnetic powder were uniformly mixed by centrifugal mixing. The resulting mixed powder was coated with polyamide resin in step (4), dried in vacuum at 130°C for 3 hours, pressed at 1400MPa for 6 seconds, and annealed in vacuum at 450°C for 0.5 hours.

[0122] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an amorphous magnetic powder core based on a flexible interface, characterized in that, Includes the following steps: (1) Add the antioxidant to a mixture of organic solvent and water, then add FeSi-based amorphous magnetic powder and dispersant, and disperse evenly to obtain a FeSi-based amorphous magnetic powder mixed solution; (2) Add nickel salt to a mixture of organic solvent and water, then add a cationic surfactant, mix thoroughly, and obtain Ni 2+ Precursor solution; (3) Ni 2+ The precursor solution was added dropwise to the FeSi-based amorphous magnetic powder mixed solution, and then a strong alkali salt solution was added dropwise until the system became alkaline. The reaction was stirred and the powder was separated, washed, and dried to obtain FeSi-based amorphous magnetic powder with a nano-scale nickel hydroxide coating. (4) FeSi-based amorphous magnetic powder with a nano-sized nickel hydroxide coating layer is mixed and coated with an insulating agent, then pressed and heat-treated to obtain an amorphous magnetic powder core based on a flexible interface.

2. The preparation method according to claim 1, characterized in that, The nickel salt in step (2) includes at least one of nickel nitrate hexahydrate, nickel chloride hexahydrate, and nickel sulfate hexahydrate; And / or, the Ni in step (2) 2+ In the precursor solution, Ni 2+ The concentration is 0.03–0.09 mol / L; And / or, the Ni in step (3) 2+ The mass ratio of nickel salt to FeSi-based amorphous magnetic powder in the precursor solution is (0.01–0.05):1; And / or, the Ni in step (3) 2+ The dropping rate of the precursor solution is 4–5 ml / min; And / or, the average particle size of the FeSi-based amorphous magnetic powder in step (1) is 15 to 45 μm.

3. The preparation method according to claim 1 or 2, characterized in that, The strong base salt in the strong base salt solution mentioned in step (3) includes at least one of sodium hydroxide, potassium hydroxide, and calcium hydroxide; And / or, the concentration of the strong base salt solution in step (3) is 0.08 to 0.12 mol / L; And / or, the dropping rate of the strong base salt solution in step (3) is 0.6 to 0.9 mL / min; more preferably 0.7 to 0.8 mL / min; And / or, the alkalinity in step (3) refers to a pH of 9 to 11; more preferably 9.8 to 10.

2.

4. The preparation method according to claim 1 or 2, characterized in that, The cationic surfactant in step (2) includes at least one of hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, and hexadecylpyridine chloride; And / or, the amount of cationic surfactant used in step (2) is Ni 2+ The precursor solution comprises 0.035–0.045 wt% of its total mass. And / or, the stirring reaction time in step (3) is 1.5 to 2.5 h.

5. The preparation method according to claim 1 or 2, characterized in that, The antioxidant in step (1) includes at least one of sodium sulfite, sodium thiosulfate, disodium ethylenediaminetetraacetate, and ascorbic acid; And / or, the amount of antioxidant used in step (1) is 0.008 to 0.015 wt% of the FeSi-based amorphous magnetic powder; And / or, the dispersant in step (1) includes at least one of polyvinylpyrrolidone, polyacrylic acid, polyethylene glycol and ammonium polymethacrylate; And / or, the amount of dispersant used in step (1) is 0.15 to 0.25 wt% of the mass of FeSi-based amorphous magnetic powder.

6. The preparation method according to claim 1 or 2, characterized in that, The organic solvents mentioned in steps (1) and (2) include at least one of ethanol, acetone, methanol, isopropanol, acetone, and butanone; And / or, the volume ratio of the organic solvent to water in steps (1) and (2) is (75-85):(15-25); And / or, the concentration of the antioxidant in step (1) in the mixed solvent is 5 to 15 mg / L; more preferably 5 to 8 mg / L; And / or, the method of uniform dispersion in step (1) includes ultrasonic dispersion and stirring; the ultrasonic dispersion time is 10 to 30 minutes; the stirring speed is 500 to 700 rpm; And / or, the method of separating the powder in step (3) includes at least one of centrifugal separation and filtration separation.

7. The preparation method according to claim 1 or 2, characterized in that, The insulating agent in step (4) includes at least one of silicone resin, epoxy modified resin, epoxy resin, polyamide resin, phenolic resin and polyimide resin; And / or, in step (4), the mass ratio of FeSi-based amorphous magnetic powder with a nano-sized nickel hydroxide coating to the insulator is 100:(0.5-5). And / or, the pressing pressure in step (4) is 1200-2000 MPa; more preferably 1200-1800 MPa, and the holding time is 5-10 s; And / or, the temperature of the heat treatment in step (4) is 400–700°C; more preferably 480–580°C; and the time is 2–6 h; more preferably 3–4 h. And / or, the heat treatment in step (4) is carried out in a vacuum or protective atmosphere, wherein the protective atmosphere is at least one of nitrogen, hydrogen and rare gas atmosphere.

8. The preparation method according to claim 1 or 2, characterized in that, The coating method in step (4) is as follows: FeSi-based amorphous magnetic powder with a nano-sized nickel hydroxide coating layer is mixed evenly with an insulating agent and a solvent, the solvent is removed, and the mixture is dried to obtain an insulating coated mixed metal soft magnetic powder. The solvent includes at least one of xylene, acetone, anhydrous ethanol, and toluene; more preferably, it is at least one of acetone and toluene. The mass ratio of the solvent to the insulating agent is (1-30):1, preferably (10-25):1; The drying temperature is 50–250°C; more preferably 70–150°C, and the drying time is 2–4 hours.

9. An amorphous magnetic powder core based on a flexible interface prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the amorphous magnetic powder core based on a flexible interface as described in claim 9 in the fields of medium and high frequency power electronic devices, next-generation information and communication equipment, new energy vehicles and charging infrastructure.

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