A power inductor magnetic ring capable of being injection molded and a preparation method thereof

Abstract

The present invention belongs to the technical field of soft magnetic materials and high-end electronic equipment, and specifically relates to a power inductor magnetic ring that can be injection molded and a preparation method thereof. The preparation method comprises the following steps: surface-modifying magnetic powder by aminosilane coupling agent to obtain magnetic powder surface-modified by aminosilane coupling agent; mixing hydrogen-containing silicone oil, allyl glycidyl ether and organic solvent, and then adding chloroplatinic acid isopropanol solution catalyst to heat reaction to obtain epoxy-modified organic silicone adhesive; mixing the aminosilane coupling agent surface-modified magnetic powder and epoxy-modified organic silicone adhesive evenly, and then injecting them into an annular mold for drying and curing, and finally using encapsulation resin for encapsulation and protection to obtain a power inductor magnetic ring. The present invention can achieve bonding curing and insulation coating of magnetic powder under the condition of low adhesive resin content, and can obtain products with high magnetic powder content and high magnetic properties under low molding pressure.

Description

Technical Field

[0001] The invention belongs to the technical field of soft magnetic materials and high-end electronic equipment, and specifically relates to an injection moldable power inductor magnetic ring and a preparation method thereof. Background Art

[0002] As a key part of the power inductor, the power inductor magnetic ring can effectively store and release energy to improve the efficiency of the circuit. It is widely used in 3C products, communication electronics, medical equipment, new energy vehicles, aerospace and other fields. The working principle of the power inductor magnetic ring is based on the electromagnetic induction phenomenon. When current passes through the power inductor coil, a magnetic field is generated in the magnetic ring. When the current changes, the magnetic field will also change. This changing magnetic field will generate an induced electromotive force, thereby storing and releasing energy.

[0003] At present, the materials used to prepare power inductor magnetic rings mainly include ferrite soft magnetic materials, iron alloy soft magnetic materials, amorphous / nanocrystalline soft magnetic materials and composite soft magnetic materials. Ferrite has good magnetic permeability and low magnetic resistance, which can greatly improve the efficiency of power inductors. However, its saturation magnetic induction intensity is relatively small, which limits the preparation of miniaturized and lightweight products. Iron alloy soft magnetic materials and amorphous / nanocrystalline soft magnetic materials have high saturation magnetic induction intensity, but with the development of high-frequency devices, the loss of the above materials at high frequencies affects the performance of the devices. By coating a layer of insulating film on the surface of the magnetic powder particles, good insulating coating can significantly reduce the eddy current loss of the material in a high-frequency environment. The principle is that each powder particle coated with an insulating layer has a very small eddy current path inside and has a high resistivity, which can greatly reduce the eddy current loss generated by the soft magnetic composite material during operation.

[0004] For example, patent CN 114360884A discloses a method for preparing a high magnetic induction and low loss gradient nanocrystalline magnetic powder core, wherein Fe-based amorphous alloy powder is treated by discharge plasma to make the surface layer of the amorphous powder nanocrystallized, and then pressed and molded by adding a coating agent and a lubricant, and finally sintered at a temperature higher than the crystallization temperature of the Fe-based amorphous alloy powder, the nanocrystals on the surface of the powder continue to grow, and the amorphous nanocrystallization inside the powder forms a gradient difference in grain size, thereby obtaining a high magnetic induction and low loss gradient nanocrystalline magnetic powder core with large grains in the outer layer and small grains in the inner layer. However, the coating agent used is MQ silicone resin, which has a weak binding force with magnetic powder, and its content needs to be increased to improve the insulation coating effect. However, the increase in the coating agent content reduces the magnetic powder content and density, affects its comprehensive magnetic properties, and is not conducive to the development direction of device miniaturization. And its molding pressure must reach more than 1GPa, which is difficult to apply to general injection molding.

[0005] Patent CN 103151134 A discloses a silicone resin-ferrite composite coated soft magnetic powder core, which couples the surface-modified soft magnetic metal particles to improve the insulation coating effect and the bonding force with the magnetic powder. However, it does not disclose how the liquid silicone resin is covalently bonded to the coupled soft magnetic metal particles, and how to improve the bonding effect. At the same time, its molding pressure is still high. Summary of the invention

[0006] In view of the above shortcomings and deficiencies in the prior art, the primary purpose of the present invention is to provide a method for preparing a power inductor magnetic ring that can be injection molded.

[0007] Another object of the present invention is to provide a power inductor magnetic ring prepared by the above method.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A method for preparing a power inductor magnetic ring that can be injection molded comprises the following preparation steps:

[0010] (1) Surface modification of magnetic powder: surface modification of magnetic powder by using an aminosilane coupling agent to obtain magnetic powder surface modified by the aminosilane coupling agent;

[0011] (2) Preparation of epoxy-modified organic silicone adhesive: mixing hydrogenated silicone oil, allyl glycidyl ether and an organic solvent, then adding a chloroplatinic acid isopropanol solution catalyst and heating the mixture to obtain an epoxy-modified organic silicone adhesive;

[0012] (3) Preparation of initial magnetic ring: The magnetic powder surface-modified with aminosilane coupling agent of step (1) and the epoxy-modified organic silicone adhesive of step (2) are mixed evenly, and then injected into a ring-shaped mold, dried and cured to obtain an initial magnetic ring;

[0013] (4) Packaging and protection: The initial magnetic ring obtained in step (3) is packaged and protected with a packaging resin to obtain a power inductor magnetic ring.

[0014] Furthermore, the magnetic powder in step (1) is one or more of iron-nickel soft magnetic alloy powder, iron-silicon soft magnetic alloy powder, iron-silicon-aluminum soft magnetic alloy powder, iron-silicon-chromium soft magnetic alloy powder, iron-nickel-molybdenum soft magnetic alloy powder, and amorphous / nanocrystalline soft magnetic alloy powder with a D50 particle size of 5 to 150 μm.

[0015] Furthermore, the aminosilane coupling agent in step (1) is one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-aminoethyl-3-aminopropyltrimethoxysilane, and N-aminoethyl-3-aminopropyltriethoxysilane.

[0016] Further preferably, the amount of the aminosilane coupling agent used is 0.1% to 1% of the mass of the magnetic powder.

[0017] Furthermore, the surface modification method in step (1) is as follows:

[0018] The magnetic powder is added into a drum dryer, and the aminosilane coupling agent solution and water are first sprayed at normal pressure and 40-60°C for surface modification reaction. After the reaction is completed, vacuum is evacuated and the temperature is raised to 70-100°C for drying to obtain magnetic powder with aminosilane coupling agent surface modified.

[0019] Further preferably, the amount of water added is 30% to 60% of the mass of the aminosilane coupling agent. The present invention can promote the dealcoholization condensation reaction of the aminosilane coupling agent on the surface of the inorganic flame retardant by adding a small amount of water during the surface modification reaction, thereby improving the surface modification effect.

[0020] The present invention adopts a surface spraying process to modify the surface of the magnetic powder, which can achieve better surface modification effect at a lower coupling agent dosage, improve the curing molding effect with the epoxy-modified organic silicone adhesive, and realize the acquisition of a product with high magnetic powder content and high magnetic properties at a lower molding pressure.

[0021] Furthermore, the hydrogen-containing silicone oil in step (2) is a hydrogen-containing silicone oil having a number average molecular weight of 1000 to 10000 and a hydrogen content of 0.2 to 1 wt.%.

[0022] Furthermore, the amount of allyl glycidyl ether used in step (2) is 5% to 30% of the mass of the hydrogen-containing silicone oil.

[0023] Furthermore, the organic solvent in step (2) is one or more of N,N-dimethylformamide, toluene, xylene, ethyl acetate, butyl acetate, n-hexane, n-heptane, acetone, butanone, tetrahydrofuran, and isopropanol.

[0024] Further preferably, the amount of the organic solvent used is 5% to 20% of the total mass of the hydrogen-containing silicone oil and allyl glycidyl ether.

[0025] Furthermore, the heating reaction in step (2) is carried out at a temperature of 70 to 90° C. and for a time of 1 to 6 hours.

[0026] Furthermore, in step (3), the mass ratio of the aminosilane coupling agent surface-modified magnetic powder to the epoxy-modified organic silicone adhesive is 80-99.5:0.5-20; more preferably 99-99.5:0.5-1.

[0027] Furthermore, the drying and curing molding in step (3) refers to first drying and curing at a pressure of 0 to 50 MPa and a temperature of 80 to 120° C. for 10 to 20 minutes, and then placing the magnetic ring at 60 to 90° C. for 12 to 24 hours after taking it out.

[0028] Furthermore, the encapsulation resin in step (4) is epoxy resin, and the process flow of the encapsulation protection is as described in any one of 1) to 3) below:

[0029] 1) Immerse the initial magnetic ring in epoxy resin glue for 0.1 to 60 minutes, take it out and cure it at 100 to 200°C for 6 to 12 hours, and obtain the power inductor magnetic ring after cooling;

[0030] 2) After baking the initial magnetic ring at 160-280° C. for 5-60 minutes, electrostatically spraying with epoxy resin powder is performed, and the process is repeated several times to make the thickness of the epoxy resin coating be 0.05-0.6 mm. After cooling, the power inductor magnetic ring is obtained;

[0031] 3) Pass the initial magnetic ring through the rod and preheat it to 100-260° C., use epoxy resin powder for fluidized bed roller coating, the thickness of the epoxy resin coating is 0.1-1.0 mm, and after cooling, a power inductor magnetic ring is obtained.

[0032] A power inductor magnetic ring is prepared by the above method.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The power inductor magnetic ring of the present invention is composed of magnetic powder surface-modified with an aminosilane coupling agent and a specific epoxy-modified organic silicone adhesive resin, which can achieve bonding curing and insulation coating of the magnetic powder at a lower adhesive resin content, and can obtain a product with a high magnetic powder content and high magnetic properties at a lower molding pressure. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0036] Example 1

[0037] (1) FeCuNbSiB nanocrystalline magnetic powder with a D50 particle size of 45 μm was added to a drum dryer, and firstly a 5% by mass 3-aminopropyltrimethoxysilane isopropanol solution and water were sprayed at normal pressure and 50°C for surface modification reaction, wherein the amount of 3-aminopropyltrimethoxysilane added was 0.5% by mass of the magnetic powder, and the amount of water added was 50% by mass of the 3-aminopropyltrimethoxysilane. After the reaction was completed, the mixture was vacuumed and heated to 80°C for drying to obtain magnetic powder surface modified with an aminosilane coupling agent.

[0038] (2) By mass, 100 parts of hydrogen-containing silicone oil with a number average molecular weight of 5600 and a hydrogen content of 0.52 wt.%, 20 parts of allyl glycidyl ether and 10 parts of toluene were mixed, and a chloroplatinic acid isopropanol solution catalyst with a platinum content of 50 ppm was added under nitrogen protection, heated to 80° C. and stirred for reaction for 4 hours to obtain an epoxy-modified organic silicone adhesive.

[0039] (3) Preparation of initial magnetic ring: 992 parts of the aminosilane coupling agent surface-modified magnetic powder of step (1) and 8 parts of the epoxy-modified organic silicone adhesive of step (2) were stirred at high speed and mixed evenly, left at room temperature for 1 hour, and then injected into a ring-shaped mold coated with a release agent. After applying a pressure of 30 MPa, the temperature was raised to 100°C and dried for 15 minutes. After taking out the magnetic ring, it was left at 75°C for 24 hours to obtain the initial magnetic ring.

[0040] (4) Immerse the initial magnetic ring obtained in step (3) in epoxy resin glue for 30 minutes, take it out and cure it at 120° C. for 8 hours, and obtain a power inductor magnetic ring after cooling.

[0041] Example 2

[0042] (1) FeSi soft magnetic alloy powder with a D50 particle size of 45 μm is added to a drum dryer, and firstly sprayed with a 5% by mass 3-aminopropyltrimethoxysilane isopropanol solution and water at normal pressure and 50°C for surface modification reaction, wherein the amount of 3-aminopropyltrimethoxysilane added is 0.1% by mass of the magnetic powder, and the amount of water added is 50% by mass of the 3-aminopropyltrimethoxysilane. After the reaction is completed, the mixture is vacuumed and heated to 80°C for drying to obtain magnetic powder surface-modified with an aminosilane coupling agent.

[0043] (2) By mass, 100 parts of hydrogen-containing silicone oil with a number average molecular weight of 5600 and a hydrogen content of 0.52 wt.%, 5 parts of allyl glycidyl ether and 10 parts of toluene were mixed, and a chloroplatinic acid isopropanol solution catalyst with a platinum content of 50 ppm was added under nitrogen protection, heated to 80° C. and stirred for reaction for 2 h to obtain an epoxy-modified organic silicone adhesive.

[0044] (3) Preparation of initial magnetic ring: 992 parts of the aminosilane coupling agent surface-modified magnetic powder of step (1) and 8 parts of the epoxy-modified organic silicone adhesive of step (2) were stirred at high speed and mixed evenly, left at room temperature for 1 hour, and then injected into a ring-shaped mold coated with a release agent. After applying a pressure of 30 MPa, the temperature was raised to 100°C and dried for 15 minutes. After taking out the magnetic ring, it was left at 75°C for 24 hours to obtain the initial magnetic ring.

[0045] (4) After baking the initial magnetic ring obtained in step (3) at 200° C. for 30 min, electrostatically spraying with epoxy resin powder is performed, and the process is repeated multiple times to make the thickness of the epoxy resin coating reach 0.4 mm. After cooling, a power inductor magnetic ring is obtained.

[0046] Example 3

[0047] (1) Adding an iron-nickel-molybdenum soft magnetic alloy powder with a D50 particle size of 45 μm into a rotary drum dryer, first spraying a 5% by mass 3-aminopropyltrimethoxysilane isopropanol solution and water at normal pressure and 50° C. for surface modification reaction, wherein the amount of 3-aminopropyltrimethoxysilane added is 1% by mass of the magnetic powder, and the amount of water added is 50% by mass of the 3-aminopropyltrimethoxysilane. After the reaction is completed, vacuuming is performed and the temperature is raised to 80° C. for drying to obtain a magnetic powder surface-modified with an aminosilane coupling agent.

[0048] (2) By mass, 100 parts of hydrogen-containing silicone oil with a number average molecular weight of 5600 and a hydrogen content of 0.52 wt.%, 30 parts of allyl glycidyl ether and 10 parts of toluene were mixed, and a chloroplatinic acid isopropanol solution catalyst with a platinum content of 50 ppm was added under nitrogen protection, heated to 90° C. and stirred for reaction for 6 hours to obtain an epoxy-modified organic silicone adhesive.

[0049] (3) Preparation of initial magnetic ring: 992 parts of the aminosilane coupling agent surface-modified magnetic powder of step (1) and 8 parts of the epoxy-modified organic silicone adhesive of step (2) were stirred at high speed and mixed evenly, left at room temperature for 1 hour, and then injected into a ring-shaped mold coated with a release agent. After applying a pressure of 50 MPa, the temperature was raised to 100°C and dried for 15 minutes. After taking out the magnetic ring, it was left at 75°C for 24 hours to obtain the initial magnetic ring.

[0050] (4) The initial magnetic ring obtained in step (3) is passed through a rod and preheated to 200° C., and epoxy resin powder is used for fluidized bed roller coating. The thickness of the epoxy resin coating is 0.5 mm. After cooling, a power inductor magnetic ring is obtained.

[0051] Example 4

[0052] (1) FeCuNbSiB nanocrystalline magnetic powder with a D50 particle size of 45 μm and a 5% by mass 3-aminopropyltrimethoxysilane isopropanol solution were stirred and mixed uniformly, and the amount of 3-aminopropyltrimethoxysilane added was 0.5% by mass of the magnetic powder. The temperature was raised to 50° C. for stirring reaction. After the reaction was completed, vacuum was evacuated and the temperature was raised to 80° C. for drying to obtain magnetic powder surface-modified with an aminosilane coupling agent.

[0053] Steps (2) to (4) are the same as in Example 1.

[0054] Comparative Example 1

[0055] 992 parts of aminosilane coupling agent surface-modified magnetic powder (same as in Example 1) and 8 parts of bisphenol A liquid epoxy resin glue were stirred and mixed evenly at high speed, placed at room temperature for 1 hour, and then injected into a ring-shaped mold coated with a release agent. After applying a pressure of 30 MPa, the temperature was raised to 100°C for drying and curing for 15 minutes. After taking out the magnetic ring, it was placed at 75°C for 24 hours to obtain an initial magnetic ring. The obtained initial magnetic ring was immersed in epoxy resin glue for 30 minutes, taken out and cured at 120°C for 8 hours, and cooled to obtain a power inductor magnetic ring.

[0056] Comparative Example 2

[0057] 992 parts of aminosilane coupling agent surface-modified magnetic powder (same as in Example 2) and 8 parts of bisphenol A liquid epoxy resin glue were stirred and mixed evenly at high speed, placed at room temperature for 1 hour, and then injected into a ring-shaped mold coated with a release agent. After applying a pressure of 30MPa, the temperature was raised to 100°C for drying and curing for 15 minutes. After taking out the magnetic ring, it was placed at 75°C for 24 hours to obtain an initial magnetic ring. After the obtained initial magnetic ring was baked at 200°C for 30 minutes, it was electrostatically sprayed with epoxy resin powder, and the process was repeated several times to make the thickness of the epoxy resin coating 0.4mm, and the power inductor magnetic ring was obtained after cooling.

[0058] Comparative Example 3

[0059] 992 parts of aminosilane coupling agent surface-modified magnetic powder (same as in Example 3) and 8 parts of bisphenol A liquid epoxy resin glue were stirred and mixed evenly at high speed, placed at room temperature for 1 hour, and then injected into a ring-shaped mold coated with a release agent. After applying a pressure of 50MPa, the temperature was raised to 100°C for drying and curing for 15 minutes. After taking out the magnetic ring, it was placed at 75°C for 24 hours to obtain an initial magnetic ring. The obtained initial magnetic ring was passed through a rod and preheated to 200°C, and epoxy resin powder was used for fluidized bed roller coating. The thickness of the epoxy resin coating was 0.5mm, and the power inductor magnetic ring was obtained after cooling.

[0060] The loss of the magnetic rings obtained in the above embodiments and comparative examples was tested (Pcv, 100kHz&0.2T), and the results are shown in Table 1 below.

[0061] Table 1

[0062]

[0063]

[0064] It can be seen from the above results that the present invention can be molded at a relatively low pressure to obtain a magnetic core product with a magnetic powder content of more than 99% and low loss. It can be seen from the comparison results of Examples 1 to 3 with Comparative Examples 1 to 3 that the use of the epoxy-modified organic silicone adhesive of the present invention can achieve better insulation coating and molding effects than conventional epoxy resin adhesives, and can significantly reduce magnetic core losses. It can be seen from the comparison results of Example 1 and Example 4 that the surface modification of magnetic powder by the surface spraying process of the present invention can further improve the insulation coating and molding effects, and achieve a magnetic core product with high magnetic powder content and low loss at a relatively low molding pressure.

[0065] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a power inductor magnetic ring that can be injection molded, characterized in that: The method comprises the following preparation steps: (1) Surface modification of magnetic powder: surface modification of magnetic powder by using an aminosilane coupling agent to obtain magnetic powder surface modified by the aminosilane coupling agent; (2) Preparation of epoxy-modified organic silicone adhesive: mixing hydrogenated silicone oil, allyl glycidyl ether and an organic solvent, then adding a chloroplatinic acid isopropanol solution catalyst and heating the mixture to obtain an epoxy-modified organic silicone adhesive; (3) Preparation of initial magnetic ring: The magnetic powder surface-modified with aminosilane coupling agent of step (1) and the epoxy-modified organic silicone adhesive of step (2) are mixed evenly, and then injected into a ring-shaped mold, dried and cured to obtain an initial magnetic ring; (4) Packaging and protection: The initial magnetic ring obtained in step (3) is packaged and protected with a packaging resin to obtain a power inductor magnetic ring.

2. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The magnetic powder in step (1) is one or more of iron-nickel soft magnetic alloy powder, iron-silicon soft magnetic alloy powder, iron-silicon-aluminum soft magnetic alloy powder, iron-silicon-chromium soft magnetic alloy powder, iron-nickel-molybdenum soft magnetic alloy powder, and amorphous / nanocrystalline soft magnetic alloy powder with a D50 particle size of 5 to 150 μm.

3. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The aminosilane coupling agent in step (1) is one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-aminoethyl-3-aminopropyltrimethoxysilane, and N-aminoethyl-3-aminopropyltriethoxysilane; the amount of the aminosilane coupling agent is 0.1% to 1% of the mass of the magnetic powder.

4. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The surface modification method in step (1) is as follows: The magnetic powder is added into a drum dryer, and the aminosilane coupling agent solution and water are first sprayed at normal pressure and 40-60°C for surface modification reaction. After the reaction is completed, vacuum is evacuated and the temperature is raised to 70-100°C for drying to obtain magnetic powder with aminosilane coupling agent surface modified.

5. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 4, characterized in that: The amount of water added is 30% to 60% of the mass of the aminosilane coupling agent.

6. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The hydrogen-containing silicone oil in step (2) is a hydrogen-containing silicone oil with a number average molecular weight of 1000 to 10000 and a hydrogen content of 0.2 to 1 wt.%.

7. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The amount of allyl glycidyl ether used in step (2) is 5% to 30% of the mass of the hydrogen-containing silicone oil.

8. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The organic solvent in step (2) is one or more of N,N-dimethylformamide, toluene, xylene, ethyl acetate, butyl acetate, n-hexane, n-heptane, acetone, butanone, tetrahydrofuran, and isopropanol; the amount of the organic solvent is 5% to 20% of the total mass of the hydrogen-containing silicone oil and allyl glycidyl ether.

9. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The temperature of the heating reaction in step (2) is 70-90° C. and the time is 1-6 hours.

10. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The mass ratio of the aminosilane coupling agent surface-modified magnetic powder to the epoxy-modified organic silicone adhesive in step (3) is 80-99.5:0.5-20.

11. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The mass ratio of the aminosilane coupling agent surface-modified magnetic powder and the epoxy-modified organic silicone adhesive mixed in step (3) is 99-99.5:0.5-1.

12. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The drying and curing molding in step (3) refers to first drying and curing at a pressure of 0 to 50 MPa and a temperature of 80 to 120° C. for 10 to 20 minutes, and then placing the magnetic ring at 60 to 90° C. for 12 to 24 hours after taking it out.

13. The method for preparing a power inductor magnetic ring capable of being injection molded according to claim 1, characterized in that: The encapsulation resin in step (4) is epoxy resin, and the process flow of the encapsulation protection is as follows: 1) Immerse the initial magnetic ring in epoxy resin glue for 0.1 to 60 minutes, take it out and cure it at 100 to 200°C for 6 to 12 hours, and obtain the power inductor magnetic ring after cooling; 2) After baking the initial magnetic ring at 160-280° C. for 5-60 minutes, electrostatically spraying with epoxy resin powder is performed, and the process is repeated several times to make the thickness of the epoxy resin coating be 0.05-0.6 mm. After cooling, the power inductor magnetic ring is obtained; 3) Pass the initial magnetic ring through the rod and preheat it to 100-260° C., use epoxy resin powder for fluidized bed roller coating, the thickness of the epoxy resin coating is 0.1-1.0 mm, and after cooling, a power inductor magnetic ring is obtained.

14. A power inductor magnetic ring, characterized in that: It is prepared by the method according to any one of claims 1 to 13.

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