阅读说明：本技术 一种宽温高频磁性材料及其制备方法和应用 (Wide-temperature-range high-frequency magnetic material and preparation method and application thereof ) 是由 杨明雄 于 2021-08-25 设计创作，主要内容包括：本发明公开了一种宽温高频磁性材料及其制备方法和应用。本发明的宽温高频磁性材料的组成包括七层包覆Fe-(2)O-(3)、SnO-(2)和ZrO-(2),其制备方法包括以下步骤：1)制备单层包覆Fe-(2)O-(3)；2)制备ZnO-NiO-TiO-(2)-Co-(2)O-(3)填充单层包覆Fe-(2)O-(3)；3)制备三层包覆Fe-(2)O-(3)；4)制备七层包覆Fe-(2)O-(3)；5)将七层包覆Fe-(2)O-(3)破碎后与SnO-(2)和ZrO-(2)混合进行球磨,干燥,即得宽温高频磁性材料。本发明的宽温高频磁性材料的晶粒尺寸细密均匀,使用频率可以达到3MHz以上,且高温下损耗较常规铁氧体可以降低15％以上,能够满足器件对高频化、大电流、高温下较大的温度区间低功耗的需求。(The invention discloses a wide-temperature high-frequency magnetic material and a preparation method and application thereof. The composition of the wide-temperature high-frequency magnetic material comprises seven layers of coated Fe 2 O 3 、SnO 2 And ZrO 2 The preparation method comprises the following steps: 1) preparation of Single layer coated Fe 2 O 3 (ii) a 2) Preparation of ZnO-NiO-TiO 2 ‑Co 2 O 3 Filled single layer clad Fe 2 O 3 (ii) a 3) Preparation of three-layer coated Fe 2 O 3 (ii) a 4) Preparation of seven-layer coated Fe 2 O 3 (ii) a 5) Coating seven layers with Fe 2 O 3 Crushing and then mixing with SnO 2 And ZrO 2 Mixing, ball milling and drying to obtain the wide-temperature high-frequency magnetic material. The wide-temperature high-frequency magnetic material has fine and uniform grain size, the use frequency can reach more than 3MHz, the loss at high temperature can be reduced by more than 15 percent compared with the conventional ferrite, and the high-frequency magnetic material can meet the requirements of high frequency of devices,Large temperature range and low power consumption under high current and high temperature.)

1. A wide temperature high frequency magnetic material is characterized in that: the wide-temperature high-frequency magnetic material comprises seven layers of coated Fe₂O₃、SnO₂And ZrO₂(ii) a The seven layers of coated Fe₂O₃Is sequentially Fe from inside to outside₂O₃Inner core, porous MnO-Fe₂O₃Layer, ZnO layer, first SiO₂Layer, second SiO₂Layer, Bi₂O₃Layer, SnO₂Layer and Nb₂O₅A layer; the above-mentionedPorous MnO-Fe₂O₃The holes of the layer are filled with ZnO, NiO and TiO₂And Co₂O₃。

2. The wide temperature high frequency magnetic material according to claim 1, characterized in that: the seven layers of coated Fe₂O₃、SnO₂、ZrO₂The mass ratio of (A) is 1: 0.0001-0.001: 0.0005-0.005.

3. The wide-temperature high-frequency magnetic material according to claim 1 or 2, characterized in that: said Fe₂O₃The average grain diameter of the inner core is 0.1-0.3 μm; the second SiO₂The thickness of the layer is 3nm to 5 nm; the Bi₂O₃The thickness of the layer is 0.5nm to 1 nm; the SnO₂The thickness of the layer is 1nm to 2 nm; the Nb₂O₅The thickness of the layer is 1nm to 2 nm.

4. A method for preparing a wide temperature range high frequency magnetic material as claimed in any one of claims 1 to 3, comprising the steps of:

1) MnO and Fe₂O₃Co-deposited on Fe₂O₃Surface of the powder to form porous MnO-Fe₂O₃Layer to obtain single-layer coated Fe₂O₃；

2) ZnO, NiO and TiO₂And Co₂O₃Deposited on a single layer of clad Fe₂O₃In the pores of the porous material to obtain ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃；

3) Mixing ZnO and SiO₂Sequentially deposited on ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃Surface to obtain three-layer coated Fe₂O₃；

4) Mixing SiO₂、Bi₂O₃、SnO₂And Nb₂O₅Sequentially depositing on three layers of coated Fe₂O₃Performing heat treatment on the surface to obtain seven layers of coated Fe₂O₃；

5) Coating seven layers with Fe₂O₃Crushing and then mixing with SnO₂And ZrO₂Mixing, ball milling and drying to obtain the wide-temperature high-frequency magnetic material.

5. The method for preparing a wide-temperature high-frequency magnetic material according to claim 4, wherein: step 1) the single layer coating of Fe₂O₃The MnO accounts for 42-45% by mass.

6. The method for producing a wide-temperature high-frequency magnetic material according to claim 4 or 5, characterized in that: step 2) adding the ZnO into the single-layer coated Fe₂O₃2-3% of the mass; the addition amount of the NiO in the step 2) is single-layer coated Fe₂O₃0.1-0.3% of the mass; step 2) the TiO₂Is added in a single layer coating Fe₂O₃0.1-0.3% of the mass; step 2) said Co₂O₃Is added in a single layer coating Fe₂O₃0.01-0.1% of the mass.

7. The method for producing a wide-temperature high-frequency magnetic material according to claim 4 or 5, characterized in that: the addition amount of the ZnO in the step 3) is ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃2.5-3.5% of the mass; step 3) SiO₂The addition amount of the ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃0.1-0.3% of the mass.

8. The method for producing a wide-temperature high-frequency magnetic material according to claim 4 or 5, characterized in that: and 4) carrying out heat treatment at 800-950 ℃ for 2-5 h.

9. The method for producing a wide-temperature high-frequency magnetic material according to claim 4 or 5, characterized in that: the ball milling time in the step 5) is 1-3 h.

10. Use of a wide temperature range, high frequency magnetic material according to any one of claims 1 to 3 in the preparation of a magnetic core.

Technical Field

The invention relates to the technical field of magnetic materials, in particular to a wide-temperature high-frequency magnetic material and a preparation method and application thereof.

Background

With the rapid development of the rapid charging technology, the output power of the charging head of the mobile phone has risen sharply from 5W to 120W at most, the frequency has also risen from 100kHz to as high as 3MHz, and with the rise of the output power, the heat generation of the device is more serious, and the temperature stability is very important for the device. A high-frequency large-current charging scheme is one of the commonly used rapid charging schemes, and the performance and safety of a mobile phone charging head can be directly determined by whether the magnetic core can keep low power consumption in a larger temperature range under the conditions of high frequency, large current and high temperature.

The foregoing merely provides background information related to the present invention and does not necessarily constitute prior art.

Disclosure of Invention

One of the objects of the present invention is to provide a magnetic material that can satisfy the requirements of a device for high frequency, large current, large temperature range at high temperature, and low power consumption.

The second objective of the present invention is to provide a method for preparing the magnetic material.

The invention also aims to provide an application of the magnetic material.

The technical scheme adopted by the invention is as follows:

a wide-temp. high-frequency magnetic material is composed of seven layers of Fe coated by Fe₂O₃、SnO₂And ZrO₂Seven-layer coated Fe₂O₃Is sequentially Fe from inside to outside₂O₃Inner core, porous MnO-Fe₂O₃Layer, ZnO layer, first SiO₂Layer, second SiO₂Layer, Bi₂O₃Layer, SnO₂Layer and Nb₂O₅Layer, porous MnO-Fe₂O₃The holes of the layer are filled with ZnO, NiO and TiO₂And Co₂O₃。

Preferably, the seven layers coat Fe₂O₃、SnO₂、ZrO₂The mass ratio of (A) is 1: 0.0001-0.001: 0.0005-0.005.

Preferably, said Fe₂O₃The average grain diameter of the inner core is 0.1-0.3 μm.

Preferably, the second SiO₂The thickness of the layer is 3nm to 5 nm.

Preferably, said Bi₂O₃The thickness of the layer is 0.5nm to 1 nm.

Preferably, the SnO₂The thickness of the layer is 1nm to 2 nm.

Preferably, said Nb₂O₅The thickness of the layer is 1nm to 2 nm.

The preparation method of the wide-temperature high-frequency magnetic material comprises the following steps:

1) MnO and Fe₂O₃Co-deposited on Fe₂O₃Surface of the powder to form porous MnO-Fe₂O₃Layer to obtain single-layer coated Fe₂O₃；

2) ZnO, NiO and TiO₂And Co₂O₃Deposited on a single layer of clad Fe₂O₃In the pores of the porous material to obtain ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃；

3) Mixing ZnO and SiO₂Sequentially deposited on ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃Surface to obtain three-layer coated Fe₂O₃；

4) Mixing SiO₂、Bi₂O₃、SnO₂And Nb₂O₅Sequentially depositing on three layers of coated Fe₂O₃Performing heat treatment on the surface to obtain seven layers of coated Fe₂O₃；

5) Coating seven layers with Fe₂O₃Crushing and then mixing with SnO₂And ZrO₂Mixing, ball milling and drying to obtain the wide-temperature high-frequency magnetic material.

Preferably, the single layer of Fe coated in step 1) is₂O₃The MnO accounts for 42-45% by mass.

Preferably, the addition amount of ZnO in the step 2) is single-layer coated Fe₂O₃2 to 3 percent of the mass.

Preferably, the addition amount of the NiO in the step 2) is single-layer coated Fe₂O₃0.1-0.3% of the mass.

Preferably, the TiO in the step 2)₂Is added in a single layer coating Fe₂O₃0.1-0.3% of the mass.

Preferably, the Co of step 2)₂O₃Is added in a single layer coating Fe₂O₃0.01-0.1% of the mass.

Preferably, the addition amount of the ZnO in the step 3) is ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃2.5-3.5% of the mass.

Preferably, the SiO in step 3)₂The addition amount of the ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃0.1-0.3% of the mass.

Preferably, the heat treatment in the step 4) is carried out at 800-950 ℃, and the treatment time is 2-5 h.

Preferably, the ball milling time in the step 5) is 1-3 h.

The invention has the beneficial effects that: the wide-temperature high-frequency magnetic material has fine and uniform grain size, the use frequency can reach more than 3MHz, the loss at high temperature can be reduced by more than 15% compared with the conventional ferrite, and the requirements of devices on high frequency, large current and low power consumption in a larger temperature range at high temperature can be met.

Drawings

FIG. 1 is a graph showing permeability curves of the porcelain rings of examples 1 to 4 and comparative examples 1 to 2.

Detailed Description

The invention will be further explained and illustrated with reference to specific examples.

Example 1:

a wide-temperature high-frequency magnetic material is prepared by the following steps:

1) fe having an average particle diameter of 0.3 μm by electrochemical coprecipitation₂O₃Co-precipitation of MnO and Fe on the surface of the powder₂O₃Form porous MnO-Fe₂O₃Layer to obtain single-layer coated Fe₂O₃(MnO content 42% by mass);

2) coating a single layer with Fe by chemical vapor deposition₂O₃ZnO of 3% by mass, in a single layer of coated Fe₂O₃NiO with the mass of 0.3 percent and single-layer coated Fe₂O₃TiO 0.3% by mass₂And a single layer of clad Fe₂O₃0.1% by mass of Co₂O₃Deposited on porous MnO-Fe₂O₃In the pores of the layer, ZnO-NiO-TiO is obtained₂-Co₂O₃Filled single layer clad Fe₂O₃；

3) ZnO-NiO-TiO is subjected to chemical vapor deposition₂-Co₂O₃Filled single layer clad Fe₂O₃ZnO accounting for 3.5 percent of the mass and ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃SiO 0.3% by mass₂Sequentially deposited on ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃Surface to obtain three-layer coated Fe₂O₃；

4) Coating three layers with Fe by chemical vapor deposition₂O₃Sequentially depositing SiO with the thickness of 5nm on the surface₂Layer of Bi of thickness 1nm₂O₃Layer, SnO with thickness of 2nm₂Layer and Nb with thickness of 2nm₂O₅Layer by layer, then the treatment is carried out for 2 hours at 950 ℃ to obtain seven layers of coated Fe₂O₃；

5) Coating seven layers with Fe₂O₃Crushing and then mixing with SnO₂And ZrO₂Mixing according to the mass ratio of 1:0.001:0.005, performing ball milling for 2h, and drying at 120 ℃ for 2h to obtain the wide-temperature high-frequency magnetic material.

Preparing a ceramic ring:

the wide-temperature high-frequency magnetic material of the present example and polyvinyl alcohol resin (number average molecular weight 35000g/mol) were mixed at a mass ratio of 1:0.06, and then spray-granulated in a spray tower to obtain granules having a particle size of 30 μm to 180 μm, and further 200kg/cm²The outer diameter of the ceramic ring blank is 14.6mm, the inner diameter is 9mm, the height is 3.5mm, and then the ceramic ring blank is processed for 3 hours at 1300 ℃ in the air atmosphere to obtain the ceramic ring.

Example 2:

a wide-temperature high-frequency magnetic material is prepared by the following steps:

1) on average by electrochemical coprecipitationFe having a particle size of 0.1 μm₂O₃Co-precipitation of MnO and Fe on the surface of the powder₂O₃Form porous MnO-Fe₂O₃Layer to obtain single-layer coated Fe₂O₃(MnO content by mass is 45%);

2) coating a single layer with Fe by chemical vapor deposition₂O₃ZnO 2% by mass and Fe in a single layer₂O₃NiO accounting for 0.1 percent of mass and accounting for single-layer coated Fe₂O₃TiO 0.1% by mass₂And a single layer of clad Fe₂O₃0.01% by mass of Co₂O₃Deposited on porous MnO-Fe₂O₃In the pores of the layer, ZnO-NiO-TiO is obtained₂-Co₂O₃Filled single layer clad Fe₂O₃；

3) ZnO-NiO-TiO is subjected to chemical vapor deposition₂-Co₂O₃Filled single layer clad Fe₂O₃ZnO accounting for 2.5 percent of the mass and ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃SiO 0.1% by mass₂Sequentially deposited on ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃Surface to obtain three-layer coated Fe₂O₃；

4) Coating three layers with Fe by chemical vapor deposition₂O₃Sequentially depositing SiO with the thickness of 3nm on the surface₂Layer of Bi of thickness 0.5nm₂O₃SnO of layer thickness 1nm₂Layer and Nb with thickness of 1nm₂O₅Layer by layer, then the treatment is carried out for 5 hours at 800 ℃ to obtain seven layers of coated Fe₂O₃；

5) Coating seven layers with Fe₂O₃Crushing and then mixing with SnO₂And ZrO₂Mixing according to the mass ratio of 1:0.0001:0.001, ball-milling for 2h, and drying at 120 ℃ for 2h to obtain the wide-temperature high-frequency magnetic material.

Preparing a ceramic ring:

the wide-temperature high-frequency magnetic material of the present example and a polyvinyl alcohol resin (number average molecular weight 35000g/mol) were mixed at a mass ratio of 1:0.06, and then sprayed in a spray towerInner spray granulation is carried out to prepare particles with the particle size of 30-180 mu m, and then 200kg/cm²The outer diameter of the ceramic ring blank is 14.6mm, the inner diameter is 9mm, the height is 3.5mm, and then the ceramic ring blank is processed for 3 hours at 1200 ℃ in the air atmosphere to obtain the ceramic ring.

Example 3:

a wide-temperature high-frequency magnetic material is prepared by the following steps:

1) fe having an average particle diameter of 0.2 μm by electrochemical coprecipitation₂O₃Co-precipitation of MnO and Fe on the surface of the powder₂O₃Form porous MnO-Fe₂O₃Layer to obtain single-layer coated Fe₂O₃(MnO 43.5% by mass);

2) coating a single layer with Fe by chemical vapor deposition₂O₃ZnO accounting for 2.5 percent of the mass and single-layer coated Fe₂O₃NiO accounting for 0.2 percent of mass and accounting for single-layer coated Fe₂O₃TiO 0.2% by mass₂And a single layer of clad Fe₂O₃0.05% by mass of Co₂O₃Deposited on porous MnO-Fe₂O₃In the pores of the layer, ZnO-NiO-TiO is obtained₂-Co₂O₃Filled single layer clad Fe₂O₃；

3) ZnO-NiO-TiO is subjected to chemical vapor deposition₂-Co₂O₃Filled single layer clad Fe₂O₃ZnO 3% by mass and ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃SiO 0.2% by mass₂Sequentially deposited on ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃Surface to obtain three-layer coated Fe₂O₃；

4) Coating three layers with Fe by chemical vapor deposition₂O₃Sequentially depositing SiO with the thickness of 4nm on the surface₂Layer of Bi of 0.7nm thickness₂O₃Layer, SnO with thickness of 1.5nm₂Layer and Nb with thickness of 1.5nm₂O₅Layer by layer, then the treatment is carried out for 3 hours at 900 ℃ to obtain seven layers of coated Fe₂O₃；

5) Coating seven layers with Fe₂O₃Crushing and then mixing with SnO₂And ZrO₂Mixing according to the mass ratio of 1:0.0005:0.0005, performing ball milling for 2h, and drying at 120 ℃ for 2h to obtain the wide-temperature high-frequency magnetic material.

Preparing a ceramic ring:

the wide-temperature high-frequency magnetic material of the present example and polyvinyl alcohol resin (number average molecular weight 35000g/mol) were mixed at a mass ratio of 1:0.06, and then spray-granulated in a spray tower to obtain granules having a particle size of 30 μm to 180 μm, and further 200kg/cm²The outer diameter of the ceramic ring blank is 14.6mm, the inner diameter is 9mm, the height is 3.5mm, and then the ceramic ring blank is processed for 3 hours at 1250 ℃ in the air atmosphere to obtain the ceramic ring.

Example 4:

a wide-temperature high-frequency magnetic material is prepared by the following steps:

1) fe having an average particle diameter of 0.15 μm by electrochemical coprecipitation₂O₃Co-precipitation of MnO and Fe on the surface of the powder₂O₃Form porous MnO-Fe₂O₃Layer to obtain single-layer coated Fe₂O₃(MnO content by mass is 44%);

2) coating a single layer with Fe by chemical vapor deposition₂O₃ZnO accounting for 2.3 percent of the mass and single-layer coated Fe₂O₃NiO accounting for 0.2 percent of mass and accounting for single-layer coated Fe₂O₃TiO 0.18% by mass₂And a single layer of clad Fe₂O₃0.03% by mass of Co₂O₃Deposited on porous MnO-Fe₂O₃In the pores of the layer, ZnO-NiO-TiO is obtained₂-Co₂O₃Filled single layer clad Fe₂O₃；

3) ZnO-NiO-TiO is subjected to chemical vapor deposition₂-Co₂O₃Filled single layer clad Fe₂O₃ZnO accounting for 2.8 percent of the mass and ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃SiO 0.13% by mass₂Sequentially deposited on ZnO-NiO-TiO₂-Co₂O₃Filled single layer clad Fe₂O₃Surface to obtain three-layer coated Fe₂O₃；

4) Coating three layers with Fe by chemical vapor deposition₂O₃Sequentially depositing SiO with the thickness of 3.5nm on the surface₂Layer of Bi of 0.8nm thickness₂O₃Layer, SnO with thickness of 1.6nm₂Layer and Nb with thickness of 1.2nm₂O₅Layer by layer, then the layer is processed for 4 hours at 870 ℃ to obtain seven layers of coated Fe₂O₃；

5) Coating seven layers with Fe₂O₃Crushing and then mixing with SnO₂And ZrO₂Mixing according to the mass ratio of 1:0.0003:0.0015, carrying out ball milling for 2h, and drying at 120 ℃ for 2h to obtain the wide-temperature high-frequency magnetic material.

Preparing a ceramic ring:

the wide-temperature high-frequency magnetic material of the present example and polyvinyl alcohol resin (number average molecular weight 35000g/mol) were mixed at a mass ratio of 1:0.06, and then spray-granulated in a spray tower to obtain granules having a particle size of 30 μm to 180 μm, and further 200kg/cm²The outer diameter of the ceramic ring blank is 14.6mm, the inner diameter is 9mm, the height is 3.5mm, and the ceramic ring blank is processed for 3 hours at 1230 ℃ in air atmosphere to obtain the ceramic ring.

Comparative example 1:

a magnetic material, the preparation method of which comprises the following steps:

1) 58 parts by mass of Fe₂O₃42 parts by mass of MnO, 6.5 parts by mass of ZnO, 0.3 part by mass of NiO and 0.3 part by mass of TiO₂0.1 part by mass of Co₂O₃And 0.3 part by mass of SiO₂Adding the mixture into a ball mill, performing ball milling for 5 hours, drying the mixture for 8 hours at 120 ℃, treating the mixture for 4 hours in an air atmosphere at 900 ℃, and crushing the mixture until the particle size is 1.0-1.5 microns to obtain mixed powder;

2) mixing the powder and SnO₂And ZrO₂Mixing according to the mass ratio of 1:0.001:0.005, performing ball milling for 2h, and drying at 120 ℃ for 2h to obtain the magnetic material.

Preparing a ceramic ring:

the magnetic material of the present comparative example and a polyvinyl alcohol resin(number average molecular weight 35000g/mol) at a mass ratio of 1:0.06, spray granulating in a spray tower to obtain granules with particle diameter of 30-180 μm, and 200kg/cm²The outer diameter of the ceramic ring blank is 14.6mm, the inner diameter is 9mm, the height is 3.5mm, and then the ceramic ring blank is processed for 3 hours at 1300 ℃ in the air atmosphere to obtain the ceramic ring.

Comparative example 2:

a magnetic material, the preparation method of which comprises the following steps:

1) 55 parts by mass of Fe₂O₃45 parts by mass of MnO, 4.5 parts by mass of ZnO, 0.1 part by mass of NiO, and 0.1 part by mass of TiO₂0.01 parts by mass of Co₂O₃And 0.1 part by mass of SiO₂Adding the mixture into a ball mill, performing ball milling for 5 hours, drying the mixture for 8 hours at 120 ℃, treating the mixture for 4 hours in an air atmosphere at 900 ℃, and crushing the mixture until the particle size is 1.0-1.5 microns to obtain mixed powder;

2) mixing the powder and SnO₂And ZrO₂Mixing according to the mass ratio of 1:0.0001:0.001, ball-milling for 2h, and drying at 120 ℃ for 2h to obtain the magnetic material.

Preparing a ceramic ring:

the magnetic material of the comparative example and polyvinyl alcohol resin (number average molecular weight 35000g/mol) were mixed at a mass ratio of 1:0.06, and then spray-granulated in a spray tower to obtain granules having a particle size of 30 μm to 180 μm, and further 200kg/cm²The outer diameter of the ceramic ring blank is 14.6mm, the inner diameter is 9mm, the height is 3.5mm, and then the ceramic ring blank is processed for 3 hours at 1300 ℃ in the air atmosphere to obtain the ceramic ring.

And (3) performance testing:

1) the permeability curves of the porcelain rings of examples 1 to 4 and comparative examples 1 to 2 are shown in FIG. 1.

As can be seen from fig. 1: the ceramic rings of the embodiments 1 to 4 can maintain stable magnetic permeability in the frequency range of 3MHz to 4MHz, which shows that the use frequency of the wide-temperature high-frequency magnetic material of the present invention can reach 3MHz or more.

2) The performance of the ceramic rings of examples 1 to 4 and comparative examples 1 to 2 was tested, and the test results are shown in the following table:

TABLE 1 ceramic Ring Performance test results

Note:

magnetic permeability: testing by adopting a precise electromagnetic analyzer 3260B, wherein the testing frequency is 3 MHz;

inductance reduction rate/2A current: testing by adopting a precise electromagnetic analyzer 3260B, wherein the testing frequency is 3 MHz;

pcv (core loss power): a hysteresis loop analyzer SY8218 is adopted for testing, and the testing conditions are 500kHz and 50 mT;

saturation magnetic flux density: a hysteresis loop analyzer SY8218 is adopted for testing, and the testing conditions are 1kHz and 1194A/m;

resistivity: and testing by using a volume surface resistivity tester.

As can be seen from Table 1: the loss of the ceramic rings of the embodiments 1 to 4 at different temperatures is lower than that of the ceramic rings of the comparative examples 1 to 2, and the direct current superposition performance is slightly better than that of the ceramic rings of the comparative examples 1 to 2, so that the ceramic rings have more advantages in practical high-frequency large-current application.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.