Ferrite material as well as preparation method and application thereof

Abstract

The invention provides a ferrite material and a preparation method and application thereof, the ferrite material comprises main components and auxiliary components, the main components comprise 25-35 mol% of NiO, 10-20 mol% of MnO, 0-5 mol% of ZnO and 52-60 mol% of Fe2O3, and the auxiliary components comprise Co2O3, CaCO3 and Nb2O5. The ferrite material has low magnetic conductivity and high Bs, the shrinkage rate of the ferrite material is basically consistent with that of a main material, the ferrite material can serve as an air gap material to obtain a magnetic core with segmented air gaps, and the problems that the segmented air gap magnetic core cracks when sintered, the air gap material permeates into the main material, and magnetic leakage occurs are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic materials, and relates to a ferrite material, a preparation method thereof and an application thereof. Background Art

[0002] Since the magnetic permeability of power ferrite cores is generally very high, it is easy to generate magnetic saturation with a little excitation. Therefore, in practical applications, the effective magnetic permeability is usually reduced by adding an air gap, so that the inductor can store more energy.

[0003] For example, CN 111875368A discloses a low magnetic permeability ferrite magnetic medium material, a preparation method thereof and an application thereof. The main component content of the low magnetic permeability ferrite medium material is: NiO (0.45 - 0.65) mol%, ZnO (42 - 45) mol%, CuO (9 - 11) mol%, Fe2O3 (45 - 47) mol%, and the auxiliary component content is: Co2O3 (0.15 - 0.25) wt%, MnCO3 (0.2 - 0.4) wt%, Bi2O3 (0.4 - 0.6) wt%; the magnetic material obtained by this invention has a magnetic permeability μi ≤ 3, a shrinkage rate of 12 - 20%, and a sintering temperature of 850 - 910°C, and is compatible with the power nickel-zinc LTCF material system, meeting the co-firing requirements of multiple heterogeneous materials such as ferrite magnetic medium slurry, power nickel-zinc LTCF material for LTCF power devices, and Ag conductor slurry at about 900°C; however, this material cannot be co-fired with manganese-zinc power ferrite material at a high temperature of 1120 - 1350°C to form an air gap medium. In addition, impurities such as CuO and Bi2O3 contained in the above nickel-copper-zinc material will liquefy at high temperature and easily penetrate into the main material (manganese-zinc ferrite material), resulting in abnormal grain growth and a significant decrease in the magnetic properties of the main material.

[0004] For example, CN 101607816A discloses a nickel ferrite for radio frequency band and a preparation method thereof, mainly providing a ferrite with a magnetic permeability of 10 ± 25%, excellent radio frequency loss characteristics, a high Curie temperature, etc. at a working frequency of 50 - 500 MHz; the main components of the ferrite are NiO: 35 - 45 mol%, Fe2O3: 55 - 65 mol%, and the auxiliary components are Co2O3: 0.5 - 0.8 wt%, Mn3O4: 0.5 - 2.5 wt%, V2O5: 0 - 1.0 wt%; pre-sintering is carried out in a rotary kiln, the pre-sintering temperature is 900 - 1000°C, the pre-sintering time is 20 - 40 minutes, the sanding particle size is 1.5 - 2.0 um, and the sintering temperature is 1100 - 1200°C. The pre-sintering temperature of this material is low, the powder particle size is large, and when co-fired at a high temperature of 1120 - 1350°C, the air gap material grains grow abnormally, and its shrinkage rate is inconsistent with that of the manganese-zinc ferrite main material, easily leading to defects such as cracking of the sintered core, dimensional deformation, and crystal spots.

[0005] Based on the above research, it is necessary to provide a ferrite material. The ferrite material has a low magnetic permeability and a high Bs, and can be used as an air-gap material to be co-fired with a main material of high-permeability manganese-zinc ferrite. Summary of the Invention

[0006] The purpose of the present invention is to provide a ferrite material, a preparation method and an application thereof. The ferrite material has a low magnetic permeability and a high Bs, and has a shrinkage rate substantially consistent with that of the co-fired main material of manganese-zinc ferrite. It can be used as an air-gap material to be co-fired with the manganese-zinc ferrite material to obtain a magnetic core with a segmented air gap, solving the problems of sintering cracking of the segmented air-gap magnetic core, infiltration of the air-gap material into the main material and magnetic leakage.

[0007] To achieve the purpose of this invention, the following technical solutions are adopted:

[0008] In the first aspect, the present invention provides a ferrite material. The ferrite material includes a main component and an auxiliary component. Among them, in terms of mole percentage, the main component includes:

[0009]

[0010] The auxiliary component includes Co2O3, CaCO3 and Nb2O5.

[0011] Through the cooperation of the main component and the auxiliary component, the ferrite material of the present invention can be used as an air-gap material and can be co-fired with a high-permeability manganese-zinc ferrite material to prepare a segmented air-gap magnetic core, meeting the requirements for the air-gap material: (1) The ferrite material of the present invention should be able to be co-fired with the main material of high magnetic permeability at high temperature; (2) The shrinkage rates of the ferrite and the main material should be substantially the same; (3) When the ferrite and the main material are co-fired at high temperature, the components of the ferrite can penetrate into the main material as little as possible, preventing the performance of the main material from deteriorating; (4) The ferrite material has a low magnetic permeability and a high Bs. On the one hand, it can increase the magnetic resistance of the magnetic circuit, and on the other hand, it can restrict all the magnetic force lines in the magnetic circuit from passing through the air-gap material, reducing the magnetic leakage phenomenon after adding an air gap to the magnetic circuit by the conventional method.

[0012] In terms of mole percentage, the main components include 25 - 35 mol% of NiO, for example, it can be 25 mol%, 27.5 mol%, 30 mol%, 32.5 mol% or 35 mol%, 10 - 20 mol% of MnO, for example, it can be 10 mol%, 12.5 mol%, 15 mol%, 17.5 mol% or 20 mol%, 0 - 5 mol% of ZnO, for example, it can be 0 mol%, 1 mol%, 2 mol%, 3 mol%, 4 mol% or 5 mol%, 52 - 60 mol% of Fe2O3, for example, it can be 52 mol%, 55 mol% or 60 mol%, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0013] Preferably, the main components include:

[0014]

[0015] Preferably, in terms of mass percentage, the auxiliary components include 0.05 - 0.25 wt% of Co2O3, for example, it can be 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt% or 0.25 wt%, 0.03 - 0.08 wt% of CaCO3, for example, it can be 0.03 wt%, 0.05 wt%, 0.07 wt% or 0.08 wt%, 0.01 - 0.03 wt% of Nb2O5, for example, it can be 0.01 wt%, 0.015 wt%, 0.02 wt%, 0.025 wt% or 0.03 wt%, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0016] Preferably, the average particle size of the ferrite material is 1.05 - 1.2 μm, for example, it can be 1.05 μm, 1.1 μm, 1.15 μm or 1.2 μm, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0017] Preferably, the initial permeability of the ferrite material is 10 ± 25% @ 100 kHz, which means the initial permeability is in the range of 7.5 - 12.5, for example, the initial permeability can be 7.5 @ 100 kHz, 10 @ 100 kHz or 12.5 @ 100 kHz, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0018] The ferrite material of the present invention has an ultra - low permeability, and the initial permeability of the magnetic core after sintering is 10 ± 25% @ 100 kHz.

[0019] In a second aspect, the present invention provides a preparation method of the ferrite material as described in the first aspect, and the preparation method includes the following steps:

[0020] Mix NiO, MnO, ZnO, Fe2O3, Co2O3, CaCO3 and Nb2O5 according to the formula amounts, and perform mixing, pre-sintering and granulation to obtain the ferrite material.

[0021] Preferably, the temperature of the pre-sintering is 980 - 1050 °C. For example, it can be 980 °C, 1000 °C, 1020 °C, 1040 °C or 1050 °C, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0022] The pre-sintering temperature of the present invention will affect the shrinkage rate of the prepared ferrite material. If the pre-sintering temperature is too high, the shrinkage rate of the material during high-temperature sintering becomes smaller; if the pre-sintering temperature is too low, the shrinkage rate becomes larger.

[0023] Preferably, the mixing method includes dry vibration milling.

[0024] Preferably, a rotary kiln is used for pre-sintering.

[0025] Preferably, the pre-sintering time is 40 - 60 min. For example, it can be 45 min, 50 min, 55 min or 60 min, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0026] Preferably, the granulation includes sand milling and spray granulation carried out in sequence.

[0027] Preferably, an additive is added during the spray granulation.

[0028] Preferably, the additive includes PVA glue.

[0029] In a third aspect, the present invention provides an air-gap magnetic core. The air-gap magnetic core includes an air-gap material and a main material, and the air-gap material includes the ferrite material as described in the first aspect.

[0030] The ferrite material of the present invention can be used with the main material to prepare an air-gap magnetic core, and the shrinkage rate of the air-gap material during sintering at high temperature is basically the same as that of the main material, and the magnetic core will not crack.

[0031] Preferably, the air-gap magnetic core is a magnetic core with a segmented air gap.

[0032] Preferably, the structure of the air-gap magnetic core includes at least two energized coil regions and a mating surface. At least two air-gap material distribution regions are arranged between any two energized coil regions. The region outside the energized coil region and the air-gap material distribution region is the main material region. The mating surface is arranged horizontally in the middle of the air-gap magnetic core to make the air-gap magnetic core form a symmetric structure.

[0033] Preferably, the main material includes manganese-zinc ferrite material.

[0034] The composition of the air-gap material of the segmented air-gap magnetic core of the present invention is basically the same as that of the main material. The composition of the manganese-zinc ferrite main material is MnO: 30-40 mol%, for example, it can be 30 mol%, 35 mol% or 40 mol%, ZnO: 5-15 mol%, for example, it can be 5 mol%, 10 mol% or 15 mol%, Fe2O3: 50-60 mol%, 50 mol%, 55 mol% or 60 mol%, ensuring that the shrinkage rates of the air-gap material and the main material are basically the same and avoiding cracking of the magnetic core.

[0035] Preferably, the magnetic permeability of the main material is 1800-4000, for example, it can be 2000, 3000 or 4000, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0036] Preferably, the shrinkage rates of the air-gap material and the main material are independently 16-18%, for example, it can be 16%, 17% or 18%, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0037] Fourthly, the present invention provides a preparation method of the air-gap magnetic core as described in the third aspect. The preparation method includes the following steps:

[0038] Press the air-gap material and the main material, and then sinter them to obtain the air-gap magnetic core.

[0039] Preferably, the sintering temperature is 1250-1350 °C, for example, it can be 1250 °C, 1280 °C, 1300 °C or 1350 °C, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0040] The sintering temperature of the present invention is the optimal use temperature of the air-gap material. Within this temperature range, the shrinkage rate can be basically the same as that of the main material, the shrinkage rate of the magnetic core is small, and the magnetic core is prevented from cracking.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] Through the cooperation of the main components and the auxiliary components, the ferrite material of the present invention can be used as the air-gap material and co-fired with the high-magnetic-permeability manganese-zinc ferrite material to prepare a segmented air-gap magnetic core, meeting the requirements for the air-gap material. Description of the Drawings

[0043] Figure 1 It is a schematic structural diagram of the air-gap magnetic core described in Embodiment 1 of the present invention;

[0044] Among them, 1 - main material area, 2 - air gap material distribution area, 3 - mating surface, 4 - energized coil area. Specific implementation manner

[0045] The technical solution of the present invention will be further described below through specific implementation manners. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0046] Embodiment 1

[0047] This embodiment provides a ferrite material, which includes a main component and an auxiliary component. Among them, in terms of mole percentage, the main component includes: 28 mol% of NiO, 14 mol% of MnO, 3 mol% of ZnO, and 55 mol% of Fe2O3;

[0048] The auxiliary component includes Co2O3, CaCO3, and Nb2O5. The content of Co2O3 is 0.2 wt% of the mass of the ferrite material, the content of CaCO3 is 0.06 wt% of the mass of the ferrite material, and the content of Nb2O5 is 0.02 wt% of the mass of the ferrite material;

[0049] The preparation method of the ferrite material includes the following steps:

[0050] NiO, MnO, ZnO, Fe2O3, Co2O3, CaCO3, and Nb2O5 are dry vibratory milled according to the formula amount, and then pre-fired at a temperature of 980 °C. The obtained pre-fired material and deionized water are put into a sand mill for grinding for 90 min at a mass ratio of 5:3. Among them, the grinding medium is steel balls with a diameter of Φ6.5 mm. Then, 0.8 wt% of PVA glue is added. After the slurry and PVA glue are fully stirred and evenly mixed, the ferrite material is obtained by spray drying;

[0051] This embodiment also provides an air gap magnetic core, which includes an air gap material and a main material. The air gap material is the above-mentioned obtained ferrite material, and the main material is a Mn-Zn ferrite material (DMR95 power ferrite material of Dongci Co., Ltd., magnetic permeability 3300 ± 25%);

[0052] The air gap magnetic core is a magnetic core with a segmented air gap as shown in Figure 1 (as shown by the arrow direction), the structure of the air gap magnetic core includes two energized coil areas 4 and a mating surface 3. Two air gap material distribution areas 2 are arranged between the two energized coil areas 4. The area outside the energized coil area 4 and the air gap material distribution area 2 is the main material area 1. The mating surface 3 is arranged horizontally in the middle of the air gap magnetic core to make the air gap magnetic core form a symmetric structure; Figure 1

[0053] ​The preparation method of the air-gap magnetic core includes: as described above Figure 1 Press the material into a standard magnetic ring with dimensions of Φ25XΦ15X8, and the density is 3.05±0.05 g / cm 3 , and then sinter the above magnetic ring in a nitrogen-protected kiln at 1300 °C.

[0054] Example 2

[0055] This example provides a ferrite material, which includes a main component and an auxiliary component. Among them, in terms of mole percentage, the main component includes: 30 mol% of NiO, 14 mol% of MnO, 1 mol% of ZnO, 55 mol% of Fe2O3;

[0056] The auxiliary component includes Co2O3, CaCO3 and Nb2O5. The content of Co2O3 is 0.2 wt% of the mass of the ferrite material, the content of CaCO3 is 0.06 wt% of the mass of the ferrite material, and the content of Nb2O5 is 0.02 wt% of the mass of the ferrite material;

[0057] The preparation method of the ferrite material includes the following steps:

[0058] Vibrate and grind NiO, MnO, ZnO, Fe2O3, Co2O3, CaCO3 and Nb2O5 according to the formula amount by dry method, and then pre-burn at a temperature of 1000 °C. The obtained pre-burned material and deionized water are put into a sand mill for grinding for 90 min at a mass ratio of 5:3. Among them, the grinding medium is steel balls with a diameter of Φ6.5 mm. Then add 0.8 wt% of PVA glue. After fully stirring the slurry and PVA glue evenly, spray drying is carried out to obtain the ferrite material;

[0059] This example also provides an air-gap magnetic core, which includes an air-gap material and a main material. The air-gap material is the above-obtained ferrite material, and the main material is a Mn-Zn ferrite material (DMR95 power ferrite material of Dongci Co., Ltd., magnetic permeability 3300±25%);

[0060] The air-gap magnetic core is a magnetic core with a segmented air gap. The structure of the air-gap magnetic core includes two energized coil regions and a mating surface. Two air-gap material distribution regions are arranged between the two energized coil regions. The region outside the energized coil region and the air-gap material distribution region is the main material region. The mating surface is arranged horizontally in the middle of the air-gap magnetic core, making the air-gap magnetic core form a symmetric structure;

[0061] The preparation method of the air-gap magnetic core includes: Press the material into a standard magnetic ring with dimensions of Φ25XΦ15X8, and the density is 3.05±0.05 g / cm 3, and then sinter the above magnetic ring in a nitrogen - protected kiln at 1300 °C.

[0062] Example 3

[0063] This example provides a ferrite material, which includes a main component and an auxiliary component. Among them, in terms of mole percentage, the main component includes: 35 mol% of NiO, 12 mol% of MnO, and 53 mol% of Fe2O3;

[0064] The auxiliary component includes Co2O3, CaCO3, and Nb2O5. The content of Co2O3 is 0.2 wt% of the mass of the ferrite material, the content of CaCO3 is 0.06 wt% of the mass of the ferrite material, and the content of Nb2O5 is 0.02 wt% of the mass of the ferrite material;

[0065] The preparation method of the ferrite material includes the following steps:

[0066] Vibrate and grind NiO, MnO, ZnO, Fe2O3, Co2O3, CaCO3, and Nb2O5 in dry method according to the formula amount, and then pre - sinter at a temperature of 1050 °C. The obtained pre - sintered material and deionized water are put into a sand mill for grinding for 90 min at a mass ratio of 5:3. Among them, the grinding medium is steel balls with a diameter of Φ6.5 mm. Then add 0.8 wt% of PVA glue. After fully stirring the slurry and PVA glue evenly, spray - dry to obtain the ferrite material;

[0067] This example also provides an air - gap magnetic core, which includes an air - gap material and a main material. The air - gap material is the above - obtained ferrite material, and the main material is a Mn - Zn ferrite material (DMR95 power ferrite material of Dongci Co., Ltd., magnetic permeability 3300 ± 25%);

[0068] The air - gap magnetic core is a magnetic core with a segmented air - gap. The structure of the air - gap magnetic core includes two energized coil regions and a mating surface. Two air - gap material distribution regions are arranged between the two energized coil regions. The region outside the energized coil region and the air - gap material distribution region is the main material region. The mating surface is arranged horizontally in the middle of the air - gap magnetic core, making the air - gap magnetic core form a symmetric structure;

[0069] The preparation method of the air - gap magnetic core includes: pressing the material into a standard magnetic ring with dimensions of Φ25XΦ15X8, and the density is 3.05 ± 0.05 g / cm 3 , and then sinter the above magnetic ring in a nitrogen - protected kiln at 1330 °C.

[0070] Example 4

[0071] This embodiment provides a ferrite material. Except that the content of Co2O3 is 0.25 wt% of the mass of the ferrite material, the content of CaCO3 is 0.03 wt% of the mass of the ferrite material, and the content of Nb2O5 is 0.01 wt% of the mass of the ferrite material, the rest are the same as those in Embodiment 1;

[0072] Except for the corresponding change in the air gap material, the air gap core provided in this embodiment is the same as that in Embodiment 1 in other respects.

[0073] Embodiment 5

[0074] This embodiment provides a ferrite material. Except that the main components include: 25 mol% of NiO, 15 mol% of MnO, 3 mol% of ZnO, and 57 mol% of Fe2O3, the rest are the same as those in Embodiment 2;

[0075] Except for the corresponding change in the air gap material, the air gap core provided in this embodiment is the same as that in Embodiment 2 in other respects.

[0076] Embodiment 6

[0077] This embodiment provides a ferrite material. Except that the main components include: 35 mol% of NiO, 11.5 mol% of MnO, 0.5 mol% of ZnO, and 53 mol% of Fe2O3, the rest are the same as those in Embodiment 2;

[0078] Except for the corresponding change in the air gap material, the air gap core provided in this embodiment is the same as that in Embodiment 2 in other respects.

[0079] Embodiment 7

[0080] This embodiment provides a ferrite material. Except that the main components include: 27 mol% of NiO, 16 mol% of MnO, 0 mol% of ZnO, and 57 mol% of Fe2O3, the rest are the same as those in Embodiment 2;

[0081] Except for the corresponding change in the air gap material, the air gap core provided in this embodiment is the same as that in Embodiment 2 in other respects.

[0082] Embodiment 8

[0083] This embodiment provides a ferrite material. Except that the main components include: 28 mol% of NiO, 12 mol% of MnO, 5 mol% of ZnO, and 55 mol% of Fe2O3, the rest are the same as those in Embodiment 2;

[0084] Except for the corresponding change in the air-gap material, the air-gap core provided in this embodiment is the same as that in Embodiment 2 in other respects.

[0085] Embodiment 9

[0086] This embodiment provides a ferrite material. Except that the main components include: 31 mol% of NiO, 10 mol% of MnO, 2 mol% of ZnO, and 57 mol% of Fe2O3, the rest is the same as that in Embodiment 2;

[0087] Except for the corresponding change in the air-gap material, the air-gap core provided in this embodiment is the same as that in Embodiment 2 in other respects.

[0088] Embodiment 10

[0089] This embodiment provides a ferrite material. Except that the main components include: 25 mol% of NiO, 20 mol% of MnO, 2 mol% of ZnO, and 53 mol% of Fe2O3, the rest is the same as that in Embodiment 2;

[0090] Except for the corresponding change in the air-gap material, the air-gap core provided in this embodiment is the same as that in Embodiment 2 in other respects.

[0091] Embodiment 11

[0092] This embodiment provides a ferrite material. Except that the pre-burning temperature in its preparation method is 980 °C, the rest is the same as that in Embodiment 2;

[0093] Except for the corresponding change in the air-gap material, the air-gap core provided in this embodiment is the same as that in Embodiment 2 in other respects.

[0094] Embodiment 12

[0095] This embodiment provides a ferrite material. Except that the pre-burning temperature in its preparation method is 1050 °C, the rest is the same as that in Embodiment 2;

[0096] Except for the corresponding change in the air-gap material, the air-gap core provided in this embodiment is the same as that in Embodiment 2 in other respects.

[0097] Embodiment 13

[0098] This embodiment provides a ferrite material, which is the same as that in Embodiment 2;

[0099] Except that the sintering temperature during the preparation of the air-gap core in this embodiment is 1250 °C, the rest is the same as that in Embodiment 2.

[0100] Embodiment 14

[0101] This embodiment provides a ferrite material, which is the same as that in Embodiment 2;

[0102] Except that the sintering temperature during the preparation of the air-gap magnetic core provided in this embodiment is 1350 °C, the rest are the same as those in Embodiment 2.

[0103] Comparative Example 1

[0104] This comparative example provides a ferrite material. Except that the main components include: 24.0 mol% of NiO, 16.0 mol% of MnO, 8.0 mol% of ZnO, and 52 mol% of Fe2O3, the rest are the same as those in Embodiment 2;

[0105] Except that the air-gap material of the air-gap magnetic core provided in this embodiment changes accordingly, the rest are the same as those in Embodiment 2.

[0106] Comparative Example 2

[0107] This comparative example provides a ferrite material. Except that the main components include: 24.0 mol% of NiO, 15.0 mol% of MnO, 1.0 mol% of ZnO, and 60 mol% of Fe2O3, the rest are the same as those in Embodiment 2;

[0108] Except that the air-gap material of the air-gap magnetic core provided in this embodiment changes accordingly, the rest are the same as those in Embodiment 2.

[0109] Comparative Example 3

[0110] This comparative example provides a ferrite material. Except that the main components include: 25.0 mol% of NiO, 23.0 mol% of MnO, and 52 mol% of Fe2O3, the rest are the same as those in Embodiment 2;

[0111] Except that the air-gap material of the air-gap magnetic core provided in this embodiment changes accordingly, the rest are the same as those in Embodiment 2.

[0112] The shrinkage rate, magnetic permeability, and Bs of the air-gap magnetic cores provided in the above embodiments and comparative examples, as well as the composition and preparation conditions of the air-gap materials and the sintering temperature of the air-gap magnetic cores, are shown in Table 1.

[0113] Table 1

[0114]

[0115]

[0116] As can be seen from Table 1:

[0117] The ferrite material obtained by the present invention can be used as an air gap material, so as to prepare a magnetic core with a segmented air gap. The shrinkage rate of the magnetic core is in the range of 16-18, the magnetic permeability is in the range of 7.5-12.5, and Bs is in the range of ≥480 mT. It can be seen from Example 2 and Examples 5-10 that the selection of the component content of the main component will affect the performance of the magnetic core. It can be seen from Example 2 and Examples 11-12 that the pre-burning temperature of the present invention will also affect the shrinkage rate of the ferrite material. It can be seen from Example 2 and Examples 13-14 that within the optimal sintering temperature of the ferrite material of the present invention, the shrinkage rate of the magnetic core can be made smaller and the performance of the magnetic core is more excellent.

[0118] In summary, the present invention provides a ferrite material, a preparation method and an application thereof. The ferrite material has a low magnetic permeability, a high Bs, and is basically consistent with the shrinkage rate of the main material of the co-fired manganese-zinc ferrite. It can be used as an air gap material to be co-fired with the manganese-zinc ferrite material to obtain a magnetic core with a segmented air gap, solving the problems of sintering cracking of the segmented air gap magnetic core, infiltration of the air gap material into the main material, and magnetic leakage.

[0119] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of within the technical scope disclosed by the present invention by those skilled in the art all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A ferrite material, characterized in that, The ferrite material includes a main component and an auxiliary component. Among them, in terms of mole percentage, the main component includes: The auxiliary component includes Co2O3, CaCO3, and Nb2O5.

2. The ferrite material according to claim 1, characterized in that, In terms of mole percentage, the main component includes: Preferably, in terms of mass percentage, the auxiliary component includes: Co2O3 0.05 - 0.25wt% CaCO3 0.03 - 0.08wt% Nb2O5 0.01 - 0.03wt%; Preferably, the average particle size of the ferrite material is 1.05 - 1.2 μm; Preferably, the initial permeability of the ferrite material is 10 ± 25% @ 100 kHz.

3. A method for preparing a ferrite material as described in claim 1 or 2, characterized in that, The preparation method includes the following steps: Mix, pre-burn, and granulate NiO, MnO, ZnO, Fe2O3, Co2O3, CaCO3, and Nb2O5 according to the formula amount to obtain the ferrite material.

4. The preparation method according to claim 3, characterized in that, The temperature of the pre-burning is 980 - 1050 °C; Preferably, a rotary kiln is used for the pre-burning; Preferably, the pre-burning time is 40 - 60 min; Preferably, the mixing method includes dry vibration milling.

5. The preparation method according to claim 3 or 4, characterized in that, The granulation includes sand milling and spray granulation carried out in sequence; Preferably, an additive is added during the spray granulation; Preferably, the additive includes PVA glue.

6. An air-gap magnetic core, characterized in that, The air-gap magnetic core includes an air-gap material and a main material, and the air-gap material includes the ferrite material as described in claim 1 or 2.

7. The air-gap magnetic core according to claim 6, wherein, The air-gap magnetic core is a magnetic core with a segmented air gap; Preferably, the structure of the air-gap magnetic core includes at least two energized coil regions and a mating surface. At least two air-gap material distribution regions are arranged between any two of the energized coil regions. The region outside the energized coil regions and the air-gap material distribution regions is the main material region. The mating surface is arranged horizontally in the middle of the air-gap magnetic core to make the air-gap magnetic core form a symmetric structure.

8. The air-gap magnetic core according to claim 6 or 7, characterized in that, The main material includes a Mn-Zn ferrite material; Preferably, the permeability of the main material is 1800 - 4000; Preferably, the shrinkage rates of the air-gap material and the main material are independently 16 - 18%; 9. A method for preparing an air-gap magnetic core according to any one of claims 6-8, characterized in that, The preparation method includes the following steps: Press the air-gap material and the main material, and then sinter them to obtain the air-gap magnetic core.

10. The preparation method according to claim 9, characterized in that, The sintering temperature is 1250 - 1350 °C.

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