High-frequency low-loss iron-nickel magnetic powder core and preparation method thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANCHANG UNIV
- Filing Date
- 2026-06-23
- Publication Date
- 2026-08-07
AI Technical Summary
[0003]专利CN2025103233586公开了一种采用硝酸铝原位低温反应生成氧化铝包覆层结合磁场成形，制备出高磁导率、低功率损耗且适合大规模生产的铁镍磁粉芯，通过外加磁场促进磁化，采用低含量Ni合金粉末得到高磁导率低损耗的磁粉芯；但是该技术仍然采用了磁场进行制备，工艺要求高
[0018]第二步使用高温有机硅树脂进行绝缘包覆，利用高温有机硅树脂本身粘结性强的特点，通过物理搅拌在无水乙醇溶液中搅干后，能非常均匀的包覆在铁镍合金粉末的表面，形成致密的包覆层，有助于提升电阻率。
Smart Images
Figure CN122531909A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of soft magnetic alloy materials technology, and in particular to a high-frequency, low-loss iron-nickel magnetic powder core and its preparation method. Background Technology
[0002] Soft magnetic materials are an important industrial material. Compared to traditional ferrite materials, soft magnetic materials, due to their inherent properties—being formed under high pressure and having internal air gaps that prevent magnetic flux leakage—are widely used in practical applications such as PFC inductors, switches, and filters. With the continuous development of high technology, the development direction of inductor components is gradually moving towards miniaturization, integration, and high frequency. Therefore, researching low-loss magnetic powder cores at high frequencies has a promising future, especially in improving core parameters such as permeability and quality factor.
[0003] Patent CN2025103233586 discloses a method for preparing iron-nickel magnetic powder cores with high permeability, low power loss, and suitability for mass production by using an in-situ low-temperature reaction of aluminum nitrate to generate an alumina coating layer combined with magnetic field forming. This method promotes magnetization by applying an external magnetic field and uses low-content Ni alloy powder to obtain a magnetic powder core with high permeability and low loss. However, this technology still relies on a magnetic field for preparation, which requires sophisticated processes. Therefore, providing a high-frequency, low-loss iron-nickel magnetic powder core with lower process requirements and a simpler preparation process has become an urgent problem to be solved. Summary of the Invention
[0004] The purpose of this invention is to overcome the existing solutions and provide a high-frequency, low-loss iron-nickel magnetic powder core and its preparation method.
[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a high-frequency, low-loss iron-nickel magnetic powder core, comprising the following steps: (1) Modified powder is obtained by interfacial modification of iron-nickel alloy powder with a modifier; (2) The modified powder and the coating agent are mixed and used for insulating coating to obtain a composite powder; (3) The composite powder is cold-pressed and then heat-treated to obtain the high-frequency, low-loss iron-nickel magnetic powder core.
[0006] Preferably, in step (1), the iron-nickel alloy powder is Fe-Ni 50%; the iron-nickel alloy powder contains a component with an average particle size of 6 μm and a component with an average particle size of 11 μm, and the mass ratio of the component with an average particle size of 6 μm to the component with an average particle size of 11 μm is 5~7:3~5. In step (1), the modifier is a silane coupling agent solution; the mass concentration of the silane coupling agent solution is 0.25~1.5%.
[0007] Preferably, the mass of the silane coupling agent is 0.25 to 1.25% of the mass of the iron-nickel alloy powder.
[0008] Preferably, the temperature for interface modification in step (1) is 45~90℃, the rotation speed is 200~450rpm, and the time is 0.5~2h.
[0009] Preferably, the coating agent in step (2) is a resin solution; the mass concentration of the resin solution is 0.25~5%.
[0010] Preferably, the mass of the resin in the coating agent is 0.1-2% of the mass of the modified powder.
[0011] Preferably, the first target temperature of the heat treatment in step (3) is 250~350℃; the heating rate to the first target temperature is 3~10℃ / min; and the holding time after reaching the first target temperature is 0.5~2h.
[0012] Preferably, the second target temperature of the heat treatment in step (3) is 450~650℃; the heating rate from the first target temperature to the second target temperature is 5~10℃ / min; and the holding time after reaching the second target temperature is 1~2h.
[0013] Preferably, the third target temperature of the heat treatment in step (3) is 200~300℃; the cooling rate from the second target temperature to the third target temperature is 1~5℃ / min.
[0014] The present invention also provides a method for preparing the high-frequency, low-loss iron-nickel magnetic powder core, and the high-frequency, low-loss iron-nickel magnetic powder core obtained therefrom.
[0015] This invention provides a method for preparing high-frequency, low-loss iron-nickel magnetic powder cores at low cost, comprising the following steps: (1) interfacial modification of iron-nickel alloy powder with a modifier to obtain modified powder; (2) mixing the modified powder with a coating agent for insulating coating to obtain composite powder; (3) cold pressing the composite powder and then heat treating it to obtain the high-frequency, low-loss iron-nickel magnetic powder core. In Fe-50%Ni alloy, spherical alloy powder is selected, and after surface modification and activation with a silane coupling agent, high-temperature organosilicon resin is used as the insulating coating agent to prepare iron-nickel magnetic powder cores with high permeability, high quality factor, low loss, and applicable to large-scale industrial production, thus overcoming the shortcomings of complex and high-cost processes in high-frequency iron-nickel magnetic powder core manufacturing.
[0016] This invention uses alloy powder with a small particle size as the coating body. Due to the excessive fineness of the powder, it is difficult to form a complete shape during the pressing process. Simultaneously, it is necessary to increase the density of the magnetic powder core to improve the magnetic permeability. This invention selects to add an appropriate amount of iron-nickel alloy powder with an average particle size of 11 μm for gradation. As the content of alloy powder with an average particle size of 6 μm gradually increases, the energy storage of the magnetic powder core increases, and the quality factor also increases accordingly. Simultaneously, the magnetic permeability decreases slightly. However, the addition of alloy powder with an average particle size of 11 μm allows powders of different particle sizes to interweave and fill the particle size during pressing, increasing the density of the magnetic powder core and thus increasing the magnetic permeability.
[0017] In this invention, based on the requirements of high permeability and high resistivity (low power loss), and the need to reduce production costs, a silane coupling agent is selected as the first-step modifier. The principle is as follows: the three ethoxy groups (-OCH2CH3) at one end of the silane coupling agent molecule undergo hydrolysis in water to generate active silanol groups (-Si-OH). These silanol groups (-Si-OH) are first physically adsorbed onto the hydroxyl groups (-M-OH) on the magnetic powder surface via hydrogen bonds. Under heating conditions (such as drying), a dehydration condensation reaction occurs between the two, forming an extremely stable covalent bond (Si-O-Metal). The small "Si-O" connection structure on the magnetic powder surface represents this strong chemical anchoring. This bond is much stronger than simple physical adsorption, ensuring that the silane coupling agent molecules are firmly anchored to the magnetic powder surface and are not easily detached during subsequent processing. The other end of the silane coupling agent: After successfully anchoring to the magnetic powder surface, the amino group (-NH2) at the other end of the silane coupling agent molecule extends outward like a tentacle. The amino group is a highly reactive functional group. The silane coupling agent not only anchors the resin, but it actually participates in the resin curing process, acting as a "crosslinking agent" at the interface. It connects the previously independent resin chains on the particle surface into a dense, interlocking three-dimensional network structure. The silane coupling agent molecule acts like a bridge; the silanol end anchors the inorganic magnetic powder matrix through Si-OM bonds, while the amino end crosslinks the organic resin network through chemical reactions. This dual reaction mechanism tightly binds two originally incompatible phases into a single organic whole.
[0018] The second step involves using high-temperature silicone resin for insulation coating. Taking advantage of the strong adhesion of high-temperature silicone resin, after being physically stirred and dried in anhydrous ethanol solution, it can be very evenly coated on the surface of iron-nickel alloy powder, forming a dense coating layer, which helps to improve resistivity.
[0019] In summary, this invention utilizes spherical Fe-Ni 50% powder alloys and employs a silane coupling agent for the first-step surface modification and activation. This results in an exceptionally active alloy powder surface, facilitating the subsequent second-step coating with high-temperature silicone resin. This process produces a high-permeability, high-quality factor, and low-loss iron-nickel magnetic powder core. The process is simple, reduces production costs, and is easily mass-produced industrially, improving production efficiency. It addresses the issues of high loss and high cost in existing high-frequency iron-nickel magnetic powder cores while simultaneously meeting the requirements for high permeability and high quality factor in high-frequency, low-loss magnetic powder cores. Attached Figure Description
[0020] Figure 1 The graphs showing the effective permeability and quality factor of the magnetic powder core as a function of frequency in the examples are shown. Figure 2 This is an SEM image of the product from Example 3. Detailed Implementation
[0021] This invention provides a method for preparing a high-frequency, low-loss iron-nickel magnetic powder core, comprising the following steps: (1) Modified powder is obtained by interfacial modification of iron-nickel alloy powder with a modifier; (2) The modified powder and the coating agent are mixed and used for insulating coating to obtain a composite powder; (3) The composite powder is cold-pressed and then heat-treated to obtain the high-frequency, low-loss iron-nickel magnetic powder core.
[0022] In this invention, the iron-nickel alloy powder in step (1) is Fe-Ni 50%, wherein Fe is 50% and Ni is 50%; the iron-nickel alloy powder contains a component with an average particle size of 6 μm and a component with an average particle size of 11 μm, and the mass ratio of the component with an average particle size of 6 μm to the component with an average particle size of 11 μm is preferably 5~7:3~5, more preferably 5.5~6.5:3.5~4.5, and more preferably 5.8~6.2:3.8~4.2.
[0023] In this invention, the modifier in step (1) is a silane coupling agent solution; the solvent of the silane coupling agent solution is ethanol, and the silane coupling agent is a methacryloyloxysilane coupling agent; the mass concentration of the silane coupling agent solution is 0.25~1.5%, more preferably 0.5~1.35%, and more preferably 1.0~1.25%.
[0024] In this invention, the mass of the silane coupling agent is preferably 0.25-1.25% of the mass of the iron-nickel alloy powder, more preferably 0.4-1.0%, and even more preferably 0.5-0.8%.
[0025] In this invention, the temperature for interface modification in step (1) is preferably 45~90℃, more preferably 50~85℃, and even more preferably 60~75℃; the rotation speed is preferably 200~450rpm, more preferably 250~400rpm, and even more preferably 300~350rpm; and the time is preferably 0.5~2h, more preferably 1~2h, and even more preferably 1.5~2h.
[0026] In this invention, after the interface modification is completed, drying is carried out. First, all the ethanol is evaporated in a water bath. The water bath temperature is preferably 60~80℃, more preferably 65~75℃, and more preferably 68~72℃. After the water bath, drying is carried out. The drying temperature is preferably 80~120℃, more preferably 90~110℃, and more preferably 95~105℃. The modified powder is obtained by drying to constant weight.
[0027] In this invention, the coating agent in step (2) is a resin solution, the solvent of the resin solution is ethanol, the resin is a high-temperature organosilicon resin, and the mass concentration of the resin solution is preferably 0.25~5%, more preferably 0.5~3%, and more preferably 0.75~1.5%.
[0028] In this invention, the mass of resin in the coating agent is preferably 0.1 to 2.0% of the mass of the modified powder, more preferably 0.5 to 1.5%, and even more preferably 0.8 to 1.2%.
[0029] In this invention, the modified powder and the coating agent are mixed at a speed preferably of 200-450 rpm, more preferably 250-400 rpm, and even more preferably 300-350 rpm. The mixture is thoroughly mixed to obtain a slurry, which is then dried. First, all ethanol is evaporated in a water bath at a temperature preferably of 60-85°C, more preferably 65-80°C, and even more preferably 68-75°C. After the water bath, the mixture is dried at a temperature preferably of 100-140°C, more preferably 110-130°C, and even more preferably 115-125°C. The drying time is preferably ≥2 hours, more preferably ≥3 hours, and even more preferably ≥4 hours. After drying, a composite powder is obtained.
[0030] In this invention, the composite powder is cold-pressed to facilitate subsequent heat treatment; the surface pressure of the pressing is preferably 25~65 MPa, more preferably 30~60 MPa, and even more preferably 35~55 MPa; the holding time is preferably 30~120s, more preferably 40~100s, and even more preferably 60~90s; the green body obtained by pressing is then heat-treated.
[0031] In this invention, the heat treatment in step (3) is carried out in a protective atmosphere, which is nitrogen, argon or helium; the first target temperature of the heat treatment is preferably 250~350℃, more preferably 260~340℃, and more preferably 280~320℃; the heating rate to the first target temperature is preferably 3~10℃ / min, more preferably 4~8℃ / min, and more preferably 5~6℃ / min; the holding time after reaching the first target temperature is preferably 0.5~2h, more preferably 0.8~1.5h, and more preferably 1~1.2h.
[0032] In this invention, the second target temperature of heat treatment in step (3) is preferably 450~650℃, more preferably 500~600℃, and even more preferably 520~550℃; the heating rate from the first target temperature to the second target temperature is preferably 5~10℃ / min, more preferably 6~9℃ / min, and even more preferably 7~8℃ / min; the holding time after reaching the second target temperature is preferably 1~2h, more preferably 1.2~1.8h, and even more preferably 1.4~1.6h.
[0033] In this invention, the third target temperature of heat treatment in step (3) is preferably 200~300℃, more preferably 220~270℃, and even more preferably 230~250℃; the cooling rate from the second target temperature to the third target temperature is preferably 1~5℃ / min, more preferably 2~4℃ / min, and even more preferably 2.5~3℃ / min; after reaching the third target temperature, it is naturally cooled to room temperature to obtain a high-frequency, low-loss iron-nickel magnetic powder core.
[0034] The present invention also provides a method for preparing the high-frequency, low-loss iron-nickel magnetic powder core, and the high-frequency, low-loss iron-nickel magnetic powder core obtained therefrom.
[0035] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0036] Example 1
[0037] Raw material preparation: FeNi spherical magnetic powder with an average particle size of 6μm and FeNi spherical magnetic powder with an average particle size of 11μm were premixed in a mixing ratio of 6:4. Interface modification: An ethanol solution with a mass fraction of 1.25% methacryloyloxysilane coupling agent was added to the mixed magnetic powder, and stirred for 1 hour at 300 r / min under a water bath heating condition of 70℃ to obtain slurry 1, wherein the content of methacryloyloxysilane coupling agent added accounted for 0.5% of the mass of the powder; First drying: After washing the slurry 1 with anhydrous ethanol, all the ethanol was evaporated at 70°C, and then it was placed in an oven and dried at 120°C for 2 hours to obtain mixed powder 1. Insulation treatment: A 2.5% (w / w) ethanol solution of high-temperature silicone resin was added to mixed powder 1 and stirred at 300 r / min for 1 h to obtain slurry 2, wherein the amount of high-temperature silicone resin added accounted for 1.0% of the powder mass; Second drying: After rinsing slurry 2 with anhydrous ethanol, evaporate all the ethanol in a water bath at 70°C, put it in an oven and dry it at 120°C for 2 hours to obtain powder 2; Granulation: The obtained powder 2 is sieved through a 200-mesh sieve to obtain granulated coated powder; Compression molding: After granulation, add 3‰ zinc stearate to the powder, then add 2 drops of polyvinyl alcohol solution, mix well, and pour into a mold. Press with a gauge pressure of 35MPa, and hold for 90s. Heat treatment: The pressed green magnetic powder core is placed in a tube furnace and heated in stages under nitrogen atmosphere at a rate of 5℃ / min. The temperature is raised to 300℃ and held for 1 hour. Then the temperature is raised again at a rate of 8℃ / min to 450℃ and held for 1 hour. The temperature is lowered at a rate of 3℃ / min and cooled to room temperature with the furnace to obtain the magnetic powder core.
[0038] Example 2
[0039] Raw material preparation: FeNi spherical magnetic powder with an average particle size of 6μm and FeNi spherical magnetic powder with an average particle size of 11μm were premixed in a mixing ratio of 6:4. Interface modification: A 1.25% (w / w) ethanol solution of methacryloyloxysilane coupling agent was added to the mixed magnetic powder, and the mixture was stirred at 300 r / min for 1 h under a water bath heating condition at 70℃ to obtain slurry 1, wherein the content of methacryloyloxysilane coupling agent added accounted for 0.5% of the powder by mass. First drying: After washing slurry 1 with anhydrous ethanol, all the ethanol was evaporated at 70°C, and the slurry was placed in an oven and dried at 100°C for 2 hours to obtain mixed powder 1. Insulation treatment: A 2.5% ethanol solution of high-temperature silicone resin was added to mixed powder 1 and stirred at 300 r / min for 1 h to obtain slurry 2, wherein the amount of high-temperature silicone resin added accounted for 1.0% of the powder mass; Second drying: After rinsing slurry 2 with anhydrous ethanol, evaporate all the ethanol in a water bath at 70°C, put it in an oven and dry it at 120°C for 4 hours to obtain powder 2; Granulation: The obtained powder 2 is sieved through a 200-mesh sieve to obtain granulated coated powder; Compression molding: After granulation, add 3‰ zinc stearate to the powder, then add 2 drops of polyvinyl alcohol solution, mix well, and pour into a mold. Press with a gauge pressure of 35MPa, and hold for 90s. Heat treatment: The pressed green magnetic powder core is placed in a tube furnace and heated in stages under nitrogen atmosphere at a rate of 5℃ / min. The temperature is raised to 300℃ and held for 1 hour. Then the temperature is raised again at a rate of 8℃ / min to 500℃ and held for 1 hour. The temperature is lowered at a rate of 3℃ / min and cooled to room temperature with the furnace to obtain the magnetic powder core.
[0040] Example 3
[0041] Raw material preparation: FeNi spherical magnetic powder with an average particle size of 6μm and FeNi spherical magnetic powder with an average particle size of 11μm were premixed in a mixing ratio of 6:4. Interface modification: An ethanol solution with a mass fraction of 1.25% methacryloyloxysilane coupling agent was added to the mixed magnetic powder, and the mixture was stirred at 300 r / min for 1 h under a water bath heating condition of 70℃ to obtain slurry 1, wherein the content of silane coupling agent added accounted for 0.5% of the mass of the powder; First drying: After washing slurry 1 with ethanol, all the ethanol was evaporated at 70℃, and then it was placed in an oven and dried at 100℃ for 2 hours to obtain mixed powder 1. Insulation treatment: A 2.5% (w / w) ethanol solution of high-temperature silicone resin was added to mixed powder 1 and stirred at 300 r / min for 1 h to obtain slurry 2, wherein the amount of high-temperature silicone resin added accounted for 1.0% of the powder mass; Second drying: After rinsing slurry 2 with anhydrous ethanol, evaporate all the ethanol in a water bath at 70°C, and dry it in an oven at 120°C for 4 hours to obtain powder 2; Granulation: The obtained powder 2 is sieved through a 200-mesh sieve to obtain granulated coated powder; Compression molding: After granulation, add 3‰ zinc stearate to the powder, then add 2 drops of polyvinyl alcohol solution, mix well, and pour into a mold. Press with a gauge pressure of 55MPa, and hold for 90s. Heat treatment: The pressed green magnetic powder core is placed in a tube furnace and heated in stages under nitrogen atmosphere. The heating rate is 5℃ / min. After heating to 300℃ and holding for 1 hour, the temperature is increased to 550℃ at 8℃ / min and held for 1 hour. The temperature is then reduced to 250℃ at 3℃ / min and cooled to room temperature with the furnace to obtain the magnetic powder core.
[0042] Example 4
[0043] Raw material preparation: FeNi spherical magnetic powder with an average particle size of 6μm and FeNi spherical magnetic powder with an average particle size of 11μm were premixed in a mixing ratio of 6:4. Interface modification: An ethanol solution with a mass fraction of 1.25% methacryloyloxysilane coupling agent was added to the mixed magnetic powder, and stirred for 1 hour at 300 r / min under a water bath heating condition of 70℃ to obtain slurry 1, wherein the content of methacryloyloxysilane coupling agent added accounted for 0.5% of the mass of the powder; First drying: After washing the slurry 1 with anhydrous ethanol, all the ethanol was evaporated at 70°C, and then it was placed in an oven and dried at 100°C for 2 hours to obtain mixed powder 1. Insulation treatment: A 2.5% (w / w) ethanol solution of high-temperature silicone resin was added to mixed powder 1 and stirred at 300 r / min for 1 h to obtain slurry 2, wherein the amount of high-temperature silicone resin added accounted for 1.0% of the powder mass; Second drying: After rinsing slurry 2 with anhydrous ethanol, evaporate all the ethanol in a water bath at 70°C, put it in an oven and dry it at 120°C for 4 hours to obtain powder 2; Granulation: The obtained powder 2 is sieved through a 200-mesh sieve to obtain granulated coated powder; Compression molding: After granulation, add 3‰ zinc stearate to the powder, then add 2 drops of polyvinyl alcohol solution, mix well, and pour into a mold. Press with a gauge pressure of 35MPa, and hold for 90s. Heat treatment: The pressed green magnetic powder core is placed in a tube furnace and heated in stages under nitrogen atmosphere at a rate of 5℃ / min. The temperature is raised to 300℃ and held for 1 hour. Then the temperature is raised again at a rate of 8℃ / min to 600℃ and held for 1 hour. The temperature is lowered at a rate of 3℃ / min and cooled to room temperature with the furnace to obtain the magnetic powder core.
[0044] The loss of the iron-nickel magnetic powder core in the embodiment was tested using a BH analyzer. The test conditions were 20mT@1MHz and the test coil was 15 turns of copper wire. The results are recorded in Table 1.
[0045] Table 1 Performance Test Results
[0046] The permeability and quality factor of the magnetic powder core were tested using a digital bridge under conditions of 1 kHz to 1 MHz. The microstructure of the coated magnetic powder was also analyzed. The curves showing the effective permeability and quality factor of the magnetic powder core as a function of frequency are shown below. Figure 1 As shown, Figure 1 In Table 1, (a) shows the curve of effective permeability of the magnetic powder core as a function of frequency, and (b) shows the curve of quality factor of the magnetic powder core as a function of frequency. Figure 1 It can be seen that the modified loss coating implemented in this invention has a significant effect on maximum permeability, quality factor and loss, and the effect is significant at high frequencies.
[0047] Figure 2 Here is a SEM image of the product from Example 3. Figure 2 It can be seen that the coated powder surface exhibits a uniform and dense coating layer, which significantly improves the resistivity of the material and reduces high-frequency loss.
[0048] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for producing a high-frequency low-loss Fe-Ni magnetic powder core, characterized by, Includes the following steps: (1) Modified powder is obtained by interfacial modification of iron-nickel alloy powder with a modifier; (2) The modified powder and the coating agent are mixed and used for insulating coating to obtain a composite powder; (3) The composite powder is cold-pressed and then heat-treated to obtain the high-frequency, low-loss iron-nickel magnetic powder core.
2. The method for preparing the high-frequency, low-loss iron-nickel magnetic powder core as described in claim 1, characterized in that, In step (1), the iron-nickel alloy powder is Fe-Ni 50%; the iron-nickel alloy powder contains a component with an average particle size of 6 μm and a component with an average particle size of 11 μm, and the mass ratio of the component with an average particle size of 6 μm to the component with an average particle size of 11 μm is 5~7:3~5. In step (1), the modifier is a silane coupling agent solution; the mass concentration of the silane coupling agent solution is 0.25~1.5%.
3. The method for preparing the high-frequency, low-loss iron-nickel magnetic powder core as described in claim 2, characterized in that, The mass of the silane coupling agent is 0.25~1.25% of the mass of the iron-nickel alloy powder.
4. The method for preparing the high-frequency, low-loss iron-nickel magnetic powder core as described in claim 3, characterized in that, The interface modification temperature in step (1) is 45~90℃, the rotation speed is 200~450rpm, and the time is 0.5~2h.
5. The method for preparing the high-frequency, low-loss iron-nickel magnetic powder core as described in claim 4, characterized in that, The coating agent mentioned in step (2) is a resin solution; the mass concentration of the resin solution is 0.25~5%.
6. The method for preparing the high-frequency, low-loss iron-nickel magnetic powder core as described in claim 5, characterized in that, The mass of the resin in the coating agent is 0.1-2% of the mass of the modified powder.
7. The method for preparing the high-frequency, low-loss iron-nickel magnetic powder core as described in claim 6, characterized in that, In step (3), the first target temperature for heat treatment is 250~350℃; the heating rate to the first target temperature is 3~10℃ / min; and the holding time after reaching the first target temperature is 0.5~2h.
8. The method for preparing the high-frequency, low-loss iron-nickel magnetic powder core as described in claim 7, characterized in that, In step (3), the second target temperature for heat treatment is 450~650℃; the heating rate from the first target temperature to the second target temperature is 5~10℃ / min; and the holding time after reaching the second target temperature is 1~2h.
9. The method for preparing the high-frequency, low-loss iron-nickel magnetic powder core as described in claim 8, characterized in that, The third target temperature for heat treatment in step (3) is 200~300℃; the cooling rate from the second target temperature to the third target temperature is 1~5℃ / min.
10. The high-frequency, low-loss iron-nickel magnetic powder core prepared by the preparation method of any one of claims 1 to 9.