A soft magnetic powder core and a method for manufacturing the same

Abstract

This invention relates to the field of soft magnetic materials technology, specifically disclosing a soft magnetic powder core and its preparation method. The preparation method of the soft magnetic powder core includes passivating a first metal powder, then mixing it uniformly with a second metal powder and a third metal powder to obtain a mixed powder; mixing the mixed powder, binder, and solvent, then curing, pressing, and annealing to obtain the soft magnetic powder core; the first metal powder includes iron-based nanocrystalline alloy powder, the second metal powder includes iron-based amorphous alloy powder, and the third metal powder includes carbonyl iron powder; the binder includes epoxy resin, silane coupling agent, kaolin, aminated cage-type silsesquioxane, and polyetheretherketone micropowder. Using the method of this invention, a soft magnetic powder core with high permeability and low core loss can be prepared, with an effective permeability μ... e ≥38, core loss Pcv≤190mW / cm³ (100kHz, 50mT), suitable for high-frequency, high-efficiency power electronic equipment.

Description

Technical Field

[0001] This invention relates to the field of soft magnetic materials technology, and in particular to a soft magnetic powder core and its preparation method. Background Technology

[0002] Efficient energy conversion and high-speed information processing are two core issues in global technological development. Against this backdrop, power electronics technology, as the core means of power management and control, is rapidly developing towards higher frequency, higher efficiency, and higher power density. Soft magnetic powder cores, as key basic functional materials for realizing the mutual conversion of electrical energy and magnetic energy, directly determine the overall efficiency and miniaturization level of power electronic equipment. Although cutting-edge research has made great progress, there are still technical bottlenecks that need to be overcome in the process of industrial application. For example, high-end equipment in fields such as new energy vehicles and photovoltaic / energy storage places almost contradictory demands on soft magnetic materials: they must have high saturation magnetic flux density to withstand large currents and low core loss to cope with high-frequency applications. Therefore, in the design and preparation of soft magnetic powder cores, three core issues need to be addressed: (1) maintaining the balance between conductivity and loss of the system under high-frequency operating conditions; (2) adapting to the continuous increase in equipment power to achieve lightweight and high efficiency of inductors; (3) responding to the continuous demand for cost reduction and efficiency improvement in the end market by developing new core structures and processes to reduce production costs.

[0003] Existing technologies attempt to overcome the aforementioned technical bottlenecks, but each still has its limitations, which can be summarized as follows: First, some technologies improve the mechanical and soft magnetic properties of magnetic powder cores through flattening and modified resin coating, but the soft magnetic powder used has a single composition, making it difficult to achieve comprehensive optimization of multiple magnetic properties such as saturation magnetization, resistivity, and DC bias performance. Second, some technologies prepare nanocrystalline soft magnetic powder cores based on amorphous thin strips with high iron content, reducing losses and simplifying the process by simultaneously ball milling and inorganic coating, but the magnetic performance control dimensions are limited, making it impossible to flexibly adjust the powder composition and product performance according to different application scenarios. Third, some technologies improve the high-frequency performance and insulation of materials by coating the surface of iron-based soft magnetic powder with a metal oxide / phosphate composite insulating layer, but the preparation process is relatively complex, involving multiple energy-intensive steps such as co-precipitation, ultrasonic treatment, and high-temperature calcination, which is not conducive to low-cost, large-scale production. Although this technology exhibits low losses in the high-frequency range, its comprehensive performance in mid-to-low frequency and high DC bias power application scenarios has not yet been systematically optimized.

[0004] To address the shortcomings of existing technologies, this study aims to develop a high-performance soft magnetic powder core and its preparation method. This will result in a novel high-performance soft magnetic composite material that combines high permeability and low loss characteristics in high-frequency applications. This is of great significance for promoting the development of power electronics technology and meeting the application needs of high-end equipment. Summary of the Invention

[0005] In view of this, the present invention provides a soft magnetic powder core and its preparation method. The present invention constructs a ternary composite magnetic powder core with iron-based nanocrystalline alloy powder, iron-based amorphous alloy powder, and carbonyl iron powder as the core and a specific binder as the insulating layer through multi-scale structural control, thus obtaining a high-performance soft magnetic composite material with both high permeability and low loss characteristics in high-frequency applications.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: This invention provides a method for preparing a soft magnetic powder core, comprising the following steps: S1. Passivate the first metal powder and then mix it evenly with the second and third metal powders to obtain a mixed powder. S2. Mix the powder, binder and solvent, cure the mixture, press it into shape, and anneal it to obtain a soft magnetic powder core. In S1, the first metal powder includes iron-based nanocrystalline alloy powder, the second metal powder includes iron-based amorphous alloy powder, and the third metal powder includes carbonyl iron powder. In S2, the adhesive comprises the following raw material components by mass fraction: 55%~65% epoxy resin, 15%~25% silane coupling agent, 0.5%~1.5% kaolin, 10%~20% aminated cage-type silsesquioxane, and 3%~5% polyether ether ketone micro powder.

[0007] Compared to existing technologies, the method for preparing soft magnetic powder cores provided by this invention abandons a single powder system and selects specific first, second, and third metal powders. The first metal powder, after passivation treatment, forms a dense and chemically stable thin layer on its surface, effectively blocking electrical contact between the first metal powders, suppressing core loss at high frequencies, and ensuring high permeability of the core at high frequencies. The second metal powder has low magnetocrystalline anisotropy; adding it to the soft magnetic powder core helps further reduce hysteresis loss. Synergistically with the first metal powder, it broadens the operating frequency range of the soft magnetic powder core and significantly improves its permeability at high frequencies. The third metal powder, as a filler phase, optimizes the packing density of the mixed powder, reduces the increase in magnetic reluctance caused by the air gap, and improves the overall effective permeability of the core. This invention, by selecting three specific metal powders, achieves simultaneous optimization of permeability and loss performance under high-frequency conditions through synergistic effects.

[0008] In the binder provided by this invention, the aminated cage-like silsesquioxane and epoxy resin undergo nanoscale organic-inorganic hybridization during curing, forming a uniformly dispersed organic-inorganic composite network structure, which significantly improves the thermal stability and mechanical strength of the coating layer. Meanwhile, the silane coupling agent forms a chemical bond with the aminated cage-like silsesquioxane and epoxy resin, enhancing their interfacial bonding force and further improving the performance of the soft magnetic powder core. Polyether ether ketone (PEEK) micropowder, as an organic polymer mobile phase, melts and fills the micropores between the mixed powder particles during heat treatment, forming a highly insulating and dense interfacial layer. Kaolin, as a sheet-like inorganic filler, acts as a physical barrier in the binder system, further improving interfacial density and insulation resistance. The binder system provided by this invention achieves the preparation of a highly insulating, highly thermally conductive, and highly tough interfacial layer, effectively reducing hysteresis loss. This binder also forms a flexible interface between heterogeneous metal powder particles that can buffer internal stress and reduce magnetic domain pinning, simultaneously reducing eddy current loss and hysteresis loss, and significantly improving magnetic permeability under high-frequency conditions.

[0009] Preferably, in S1, the passivation process includes the following steps: The first metal powder was added to a mixed solution of phosphoric acid aqueous solution and acetone for ultrasonic treatment, followed by washing and drying.

[0010] More preferably, the mass concentration of the phosphoric acid aqueous solution is 83% to 87%.

[0011] More preferably, the amount of the phosphoric acid aqueous solution used is 0.2% to 0.5% of the mass of the first metal powder.

[0012] More preferably, the amount of acetone used is 10% to 12% of the mass of the first metal powder.

[0013] More preferably, the ultrasonic treatment power is 150~250W and the time is 15~30min.

[0014] Preferably, in S1, the metal powder in the soft magnetic powder core comprises the following components in the following mass percentages: 30%~65% first metal powder, 25%~35% second metal powder, and 10%~45% third metal powder.

[0015] Preferably, in S1, the particle size D50 of the first metal powder is 20~80μm.

[0016] Preferably, in S1, the particle size D50 of the second metal powder is 10~50μm.

[0017] Preferably, in S1, the particle size D50 of the third metal powder is 5~10μm.

[0018] The soft magnetic powder core provided by this invention further defines the mass ratio and particle size range of the three metal powders. It forms a high-permeability magnetic flux conduction path, a high-resistivity insulating barrier, and a high-density support structure inside the core, constructing a multi-scale synergistic composite structure. The three components work together to achieve synchronous optimization of permeability and hysteresis loss.

[0019] Preferably, in S1, the iron-based amorphous alloy powder includes Fe-Si-B-Nb-Cu, Fe-Si-BC-Cr, Fe-Si-BC, Fe-Si-Cr, Fe-Si-Al, Fe-Si, or Fe-Ni.

[0020] Preferably, in S1, the iron-based nanocrystalline alloy powder includes Fe-Si-B-Nb-Cu, Fe-Si-BC-Cr, Fe-Si-BC, Fe-Si-Cr, Fe-Si-Al, Fe-Si, or Fe-Ni.

[0021] For example, the iron-based amorphous alloy powder was purchased from Ningbo Magnetic Materials Application Technology Innovation Center Co., Ltd.

[0022] Preferably, the iron-based nanocrystalline alloy powder is purchased from Hebei Mingqi Technology Co., Ltd.

[0023] In a further preferred embodiment, the iron-based nanocrystalline alloy powder is prepared by ball milling. The parameters of the ball milling are not specifically limited, but it is sufficient to grind the powder until the particle size D50 is in the range of 20~80μm.

[0024] The specific parameters of the ball mill can include the following: ball mill speed 300~400 r / min, ball-to-material ratio (8~12):1, and time 8~12 h.

[0025] Preferably, in S1, the Fe mass content in the carbonyl iron powder is 98.1%~99.9%.

[0026] Preferably, in S2, the epoxy resin includes at least one of organosilicon-modified epoxy resin, epoxy silicone resin, or polyether epoxy resin.

[0027] More preferably, in S2, the organosilicon-modified epoxy resin is purchased from Shenzhen Jipeng Silicon Fluorine Materials Co., Ltd., and the model is JP-H26.

[0028] More preferably, in S2, the epoxy silicone resin is purchased from Dongguan Sanhua Chemical Coatings Co., Ltd., and the model is SH-804.

[0029] More preferably, in S2, the polyether epoxy resin is purchased from Dongguan Sanhua Chemical Coatings Co., Ltd., and the model is ES-2000.

[0030] Preferably, in S2, the kaolin contains at least 85 wt% particles with a diameter <2 μm.

[0031] Preferably, in S2, the kaolin is purchased from Henan Keer New Materials Co., Ltd., and the model is DK-90.

[0032] Preferably, in S2, the particle size D50 of the polyether ether ketone micro powder is 5~75μm.

[0033] Preferably, in S2, the polyetheretherketone micro powder is purchased from Jilin Zhongyan Polymer Materials Co., Ltd., and the model is 330PF PEEK.

[0034] Preferably, in S2, the silane coupling agent is γ-aminopropyltriethoxysilane.

[0035] Preferably, in S2, the silane coupling agent is purchased from Zhongyu Wohao New Materials Co., Ltd., and the model is KH-550.

[0036] Preferably, in S2, the solvent includes acetone and N,N-dimethylformamide.

[0037] More preferably, in S2, the volume ratio of acetone to N,N-dimethylformamide is (1~3):1.

[0038] Preferably, in step S2, the amount of solvent added is 4 to 8 times the mass of the adhesive.

[0039] Preferably, in step S2, the amount of binder added is 2% to 6% of the mass of the mixed powder.

[0040] For example, in S2, a flow agent may also be added during curing. The flow agent comprises zinc stearate and micronized polyethylene wax in a mass ratio of 1:(1~1.5). The amount of the flow agent added is 0.3%~0.8% of the mass content of the mixed powder. The micronized polyethylene wax is purchased from Dongguan Longchuang New Material Technology Co., Ltd., and its model is P-1098.

[0041] Preferably, in S2, the curing includes a first curing and a second curing, wherein the temperature of the first curing is 80~120℃ and the temperature of the second curing is 180~220℃.

[0042] This invention further optimizes the specific parameters of the curing process, which is beneficial to further improve the permeability of the soft magnetic powder core and reduce hysteresis loss.

[0043] More preferably, the first curing time is 30-60 minutes, and the second curing time is 1-3 hours.

[0044] For example, the first curing is carried out in an inert atmosphere, which may be nitrogen.

[0045] For example, the second curing is performed under vacuum conditions.

[0046] Preferably, in step S2, the pressure during the pressing process is 600~1200MPa.

[0047] Preferably, in step S2, the annealing temperature is 380~420℃ and the time is 1~2h.

[0048] This invention provides a soft magnetic powder core, which is prepared by the above-described method for preparing soft magnetic powder cores.

[0049] The soft magnetic powder core provided by this invention is composed of three functionally complementary soft magnetic metal powders. By precisely controlling the ratio of these three powders and combining them with a binder system for insulating coating, pressing, and annealing processes, an interface layer that buffers stress and reduces losses is constructed between the soft magnetic metal powder particles. The resulting soft magnetic powder core forms an optimized three-dimensional magnetic circuit at multiple scales, effectively solving the problem of simultaneously achieving high permeability and low loss at high frequencies. Its effective permeability μ... e ≥38, core loss Pcv≤190mW / cm³ (100kHz, 50mT), suitable for high-frequency, high-efficiency power electronic equipment. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0051] In the embodiments and comparative examples of this invention, the Fe-Si-B-Nb-Cu iron-based nanocrystalline alloy powder was purchased from Hebei Mingqi Technology Co., Ltd. (1K107); the Fe-Si-B-Cr iron-based nanocrystalline alloy powder was purchased from Hebei Mingqi Technology Co., Ltd. (1K105); the Fe-Si-B-Cr iron-based amorphous alloy powder was purchased from at least one of AM1-B, AM4-B, or AM4-D from Ningbo Magnetic Materials Application Technology Innovation Center Co., Ltd.; the Fe-Si-BC iron-based amorphous alloy powder was purchased from Ningbo Magnetic Materials Application Technology Innovation Center Co., Ltd. (AM6-B); the third metal powder was carbonyl iron powder, wherein the Fe mass content was 99.9%; and the organosilicon-modified epoxy resin was purchased from Shenzhen Ji The following materials were purchased: Penggui Fluorine Materials Co., Ltd., model JP-H26; epoxy silicone resin purchased from Dongguan Sanhua Chemical Coatings Co., Ltd., model SH-804; polyether epoxy resin purchased from Dongguan Sanhua Chemical Coatings Co., Ltd., model ES-2000; polyether ether ketone micro powder purchased from Jilin Zhongyan Polymer Materials Co., Ltd., model 330PFPEEK; the silane coupling agent was γ-aminopropyltriethoxysilane, purchased from Kangjin New Materials Technology Co., Ltd., model KH-550; kaolin purchased from Henan Keer New Materials Co., Ltd., model DK-90; amino-modified cage-type silsesquioxane was AM0265; and micronized polyethylene wax purchased from Dongguan Longchuang New Materials Technology Co., Ltd., model P-1098.

[0052] Unless otherwise specified, the raw materials and reagents used in this invention are all conventional commercially available products; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0053] Example 1 This embodiment provides a method for preparing a soft magnetic powder core, including the following steps: Step 1: Based on the amount of phosphoric acid aqueous solution being 0.2% of the mass of the first metal powder and the amount of acetone being 10% of the mass of the first metal powder, the first metal powder is added to a mixed solution containing 85wt% phosphoric acid aqueous solution and acetone, ultrasonically treated at 150W for 30min, washed until neutral, and dried at 60℃ to obtain passivated first metal powder. Step 2: Mix the passivated first metal powder, second metal powder and third metal powder evenly to obtain a mixed powder; Step 3: Based on the addition amount of binder being 2% of the mass of the mixed powder and the addition amount of solvent being 4 times the mass of binder, mix the mixed powder, binder and solvent, and cure the mixture for 60 minutes under a nitrogen atmosphere and at 100°C. Then, cure it for 1 hour under vacuum conditions at 200°C to form a dense insulating layer. Based on the addition amount of flow agent being 0.3% of the mass of the mixed powder, zinc stearate and micronized polyethylene wax in a mass ratio of 1:1 are used as flow agents. Continue to add flow agents, mix evenly, press and shape under a pressure of 800MPa, and anneal at 400°C for 2 hours under inert gas protection to obtain a soft magnetic powder core. In step 1, the metal powder in the soft magnetic powder core comprises the following components by mass percentage: 40% of the first metal powder with a particle size D50 of 45 μm, 35% of the second metal powder with a particle size D50 of 15 μm, and 25% of the third metal powder with a particle size D50 of 5 μm; The first metal powder is Fe-Si-B-Nb-Cu series iron-based nanocrystalline alloy powder; the second metal powder is Fe-Si-B-Cr series iron-based amorphous alloy powder AM1-B. In step 3, the binder comprises the following raw material components by mass fraction: 60% silicone-modified epoxy resin, 20% γ-aminopropyltriethoxysilane, 1% kaolin, 14% aminated cage-type silsesquioxane, and 5% polyetheretherketone micro powder; In step 3, the solvent includes acetone and N,N-dimethylformamide in a volume ratio of 2:1.

[0054] Example 2 This embodiment provides a method for preparing a soft magnetic powder core, including the following steps: Step 1: Based on the amount of phosphoric acid aqueous solution being 1% of the mass of the first metal powder and the amount of acetone being 10% of the mass of the first metal powder, the first metal powder is added to a mixed solution containing 85wt% phosphoric acid aqueous solution and acetone, ultrasonically treated at 200W for 20min, washed until neutral, and dried at 60℃ to obtain passivated first metal powder. Step 2: Mix the passivated first metal powder, second metal powder and third metal powder evenly to obtain a mixed powder; Step 3: Based on the addition amount of binder being 6% of the mass of the mixed powder and the addition amount of solvent being 8 times the mass of binder, mix the mixed powder, binder and solvent, and cure the mixture for 40 minutes under a nitrogen atmosphere and at 80°C. Then, cure it for 3 hours under vacuum conditions at 220°C to form a dense insulating layer. Based on the addition amount of flow agent being 0.8% of the mass of the mixed powder, zinc stearate and micronized polyethylene wax with a mass ratio of 1:1.5 are used as flow agents. Continue to add flow agents, mix evenly, and press into shape under a pressure of 1000MPa. Anneal at 400°C for 2 hours under inert gas protection to obtain a soft magnetic powder core. In step 1, the metal powder in the soft magnetic powder core comprises the following components by mass percentage: 65% of the first metal powder with a particle size D50 of 80 μm, 25% of the second metal powder with a particle size D50 of 15 μm, and 10% of the third metal powder with a particle size D50 of 10 μm. The first metal powder is Fe-Si-B-Cr based iron-based nanocrystalline alloy powder; the second metal powder is Fe-Si-BC based iron-based amorphous alloy powder. In step 3, the binder comprises the following raw material components by mass fraction: 55% polyether epoxy resin, 24% γ-aminopropyltriethoxysilane, 1.5% kaolin, 15% aminated cage-like silsesquioxane, and 4.5% polyether ether ketone micro powder; In step 3, the solvent includes acetone and N,N-dimethylformamide in a volume ratio of 3:1.

[0055] Example 3 This embodiment provides a method for preparing a soft magnetic powder core, including the following steps: Step 1: Based on the amount of phosphoric acid aqueous solution being 1.5% of the mass of the first metal powder and the amount of acetone being 10% of the mass of the first metal powder, the first metal powder is added to a mixed solution containing 85wt% phosphoric acid aqueous solution and acetone, ultrasonically treated at 250W for 15min, washed until neutral, and dried at 60℃ to obtain passivated first metal powder. Step 2: Mix the passivated first metal powder, second metal powder and third metal powder evenly to obtain a mixed powder; Step 3: Based on the addition amount of binder being 5% of the mass of the mixed powder and the addition amount of solvent being 6 times the mass of binder, mix the mixed powder, binder and solvent, and cure the mixture for 50 minutes under a nitrogen atmosphere and at 120°C. Then, cure it for 2 hours under vacuum conditions at 180°C to form a dense insulating layer. Based on the addition amount of flow agent being 0.5% of the mass of the mixed powder, zinc stearate and micronized polyethylene wax with a mass ratio of 1:1.5 are used as flow agents. Continue to add flow agents, mix evenly, and press into shape under a pressure of 1200MPa. Anneal at 400°C for 2 hours under inert gas protection to obtain a soft magnetic powder core. In step 1, the metal powder in the soft magnetic powder core comprises the following components by mass percentage: 30% of a first metal powder with a particle size D50 of 60 μm, 30% of a second metal powder with a particle size D50 of 15 μm, and 40% of a third metal powder with a particle size D50 of 10 μm; The first metal powder is Fe-Si-B-Cr based iron-based nanocrystalline alloy powder; the second metal powder is Fe-Si-B-Cr based iron-based amorphous alloy powder AM4-B. In step 3, the binder comprises the following raw material components by mass fraction: 61% epoxy silicone resin, 25% γ-aminopropyltriethoxysilane, 1% kaolin, 10% aminated cage-type silsesquioxane, and 3% polyetheretherketone micro powder; In step 3, the solvent includes acetone and N,N-dimethylformamide in a volume ratio of 3:1.

[0056] Comparative Example 1 This comparative example provides a method for preparing a soft magnetic powder core. Compared with Example 1, the difference is that step 1 is omitted, and in step 2, the second metal powder and the third metal powder are mixed evenly to obtain a mixed powder. The specific differences are as follows: the metal powder in the soft magnetic powder core includes the following components by mass percentage: 55% of the second metal powder with a particle size D50 of 15 μm and 45% of the third metal powder with a particle size D50 of 5 μm; The second metal powder is Fe-Si-B-Cr based iron-based amorphous alloy powder AM1-B; The other components and preparation methods remain unchanged, and will not be repeated here.

[0057] Comparative Example 2 This comparative example provides a method for preparing a soft magnetic powder core. Compared with Example 1, the difference is that in step 2, the passivated first metal powder and third metal powder are mixed evenly to obtain a mixed powder. The specific differences are as follows: the metal powder in the soft magnetic powder core includes the following components by mass percentage: 70% of the first metal powder with a particle size D50 of 45μm and 30% of the third metal powder with a particle size D50 of 5μm; The first metal powder is Fe-Si-B-Nb-Cu series iron-based nanocrystalline alloy powder; The other components and preparation methods remain unchanged, and will not be repeated here.

[0058] Comparative Example 3 This comparative example provides a method for preparing a soft magnetic powder core. Compared with Example 1, the difference is that in step 2, the passivated first metal powder and the second metal powder are mixed evenly to obtain a mixed powder. The specific differences are as follows: the metal powder in the soft magnetic powder core includes the following components by mass percentage: 62.5% of the first metal powder with a particle size D50 of 45 μm and 37.5% of the second metal powder with a particle size D50 of 15 μm; The first metal powder is Fe-Si-B-Nb-Cu series iron-based nanocrystalline alloy powder; the second metal powder is Fe-Si-B-Cr series iron-based amorphous alloy powder AM1-B. The other components and preparation methods remain unchanged, and will not be repeated here.

[0059] Comparative Example 4 This comparative example provides a method for preparing a soft magnetic powder core. Compared with Example 1, the difference is that in step 3, the binder is replaced entirely with an equal amount of silicone resin, which was purchased from Dow Corning DC-840. The solvent was entirely replaced with an equal amount of acetone. The curing process was changed to a single curing step, specifically curing at 150°C for 2 hours in air. The specific steps are as follows: Step 1: Based on the amount of phosphoric acid aqueous solution being 0.2% of the mass of the first metal powder and the amount of acetone being 10% of the mass of the first metal powder, the first metal powder is added to a mixed solution containing 85wt% phosphoric acid aqueous solution and acetone, ultrasonically treated at 150W for 30min, washed until neutral, and dried at 60℃ to obtain passivated first metal powder. Step 2: Mix the passivated first metal powder, second metal powder and third metal powder evenly to obtain a mixed powder; Step 3: Based on the addition amount of Dow Corning DC-840 binder being 2% of the mass of the mixed powder and the addition amount of acetone being 4 times the mass of Dow Corning DC-840 binder, mix the mixed powder, Dow Corning DC-840 binder, and acetone, and cure in air at 150°C for 2 hours to form a dense insulating layer. Based on the addition amount of flow agent being 0.3% of the mass of the mixed powder, zinc stearate and micronized polyethylene wax in a mass ratio of 1:1 are used as flow agents. Continue to add flow agents, mix evenly, press and mold under a pressure of 800MPa, and anneal at 400°C for 2 hours under inert gas protection to obtain a soft magnetic powder core. In step 1, the metal powder in the soft magnetic powder core comprises the following components by mass percentage: 40% of the first metal powder with a particle size D50 of 45 μm, 35% of the second metal powder with a particle size D50 of 15 μm, and 25% of the third metal powder with a particle size D50 of 5 μm; The first metal powder is Fe-Si-B-Nb-Cu series iron-based nanocrystalline alloy powder; the second metal powder is Fe-Si-B-Cr series iron-based amorphous alloy powder AM1-B.

[0060] Comparative Example 5 This comparative example provides a method for preparing a soft magnetic powder core. Compared with Example 1, the difference is that in step 3, the binder includes the following raw material components by mass fraction: 80% organosilicon-modified epoxy resin and 20% γ-aminopropyltriethoxysilane (KH-550); The other components and preparation methods remain unchanged, and will not be repeated here.

[0061] Comparative Example 6 This comparative example provides a method for preparing a soft magnetic powder core. The difference from Example 1 is that the amino-coated cage-type silsesquioxane is replaced with an equal amount of γ-aminopropyltriethoxysilane (KH-550). The other components and preparation methods remain unchanged, and will not be repeated here.

[0062] Example of effect The effective permeability and core loss of the soft magnetic powder cores prepared by the methods provided in the examples and comparative examples were tested, as follows: The soft magnetic powder core sample was tested using a TUNKIA-TD8220 soft magnetic DC testing system to obtain its effective permeability (μ). e The results are shown in Table 1.

[0063] Table 1

[0064] As shown in Table 1, the soft magnetic powder core provided in this embodiment of the invention achieves excellent comprehensive performance with high permeability and low core loss. Its effective permeability (μ) e It can reach 38, with core loss as low as 176.5mW / cm. 3 In contrast, in Comparative Examples 1 to 6, whether the metal powder and its proportion in this invention are changed, or other binders are replaced, the permeability and core loss cannot be achieved.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a soft magnetic powder core, characterized in that, Includes the following steps: S1. Passivate the first metal powder and then mix it evenly with the second and third metal powders to obtain a mixed powder. S2. Mix the powder, binder and solvent, cure the mixture, press it into shape, and anneal it to obtain a soft magnetic powder core. In S1, the first metal powder includes iron-based nanocrystalline alloy powder, the second metal powder includes iron-based amorphous alloy powder, and the third metal powder includes carbonyl iron powder. In S2, the adhesive comprises the following raw material components by mass fraction: 55%~65% epoxy resin, 15%~25% silane coupling agent, 0.5%~1.5% kaolin, 10%~20% aminated cage-type silsesquioxane, and 3%~5% polyether ether ketone micro powder.

2. The method for preparing a soft magnetic powder core as described in claim 1, characterized in that, In S1, the passivation process includes the following steps: The first metal powder was added to a mixed solution of phosphoric acid aqueous solution and acetone for ultrasonic treatment, followed by washing and drying.

3. The method for preparing a soft magnetic powder core as described in claim 2, characterized in that, The mass concentration of the phosphoric acid aqueous solution is 83%~87%; The amount of the phosphoric acid aqueous solution used is 0.2% to 0.5% of the mass of the first metal powder; The amount of acetone used is 10% to 12% of the mass of the first metal powder; The ultrasonic treatment has a power of 150~250W and a duration of 15~30min.

4. The method for preparing a soft magnetic powder core as described in claim 1, characterized in that, In S1, the metal powder in the soft magnetic powder core comprises the following components by mass percentage: 30%~65% first metal powder, 25%~35% second metal powder, and 10%~45% third metal powder.

5. The method for preparing a soft magnetic powder core as described in claim 1 or 4, characterized in that, In S1, the particle size D50 of the first metal powder is 20~80μm; In S1, the particle size D50 of the second metal powder is 10~50μm; In S1, the particle size D50 of the third metal powder is 5~10μm.

6. The method for preparing a soft magnetic powder core as described in claim 1, characterized in that, In S2, the epoxy resin includes at least one of organosilicon-modified epoxy resin, epoxy silicone resin, or polyether epoxy resin. In S2, the particle size D50 of the polyether ether ketone micro powder is 5~75μm.

7. The method for preparing a soft magnetic powder core as described in claim 1, characterized in that, In S2, the silane coupling agent is γ-aminopropyltriethoxysilane; In S2, the amount of binder added is 2% to 6% of the mass of the mixed powder.

8. The method for preparing a soft magnetic powder core as described in claim 1, characterized in that, In S2, the curing includes a first curing and a second curing. The temperature of the first curing is 80~120℃, and the temperature of the second curing is 180~220℃.

9. The method for preparing a soft magnetic powder core as described in claim 1, characterized in that, In S2, the pressure during the pressing process is 600~1200MPa; In S2, the annealing temperature is 380~420℃ and the time is 1~2h.

10. A soft magnetic powder core, characterized in that, It is prepared by the method for preparing soft magnetic powder core according to any one of claims 1 to 9.