Nickel-zinc ferrite material, its preparation method and use

Abstract

The present application provides a nickel-zinc ferrite material, its preparation method, and use. The nickel-zinc ferrite material includes a main material containing Fe2O3, Ni2O3, ZnO, and CuO, a functional additive containing a combination of three or at least four of Mn3O4, TiO2, Ta2O5, Co2O3, and Sm2O3, and a compensator containing Fe2O3 and Ni2O3. The present application employs an appropriate main composition compensation process and adds appropriate inexpensive compensators and functional additives to the ferrite material, thereby significantly reducing the power loss at 13.56 MHz of the prepared nickel-zinc ferrite material.

Description

[Technical Field]

[0001] The present application relates to the technical field of soft ferrites, for example nickel zinc ferrite materials, their preparation methods and uses. [Background technology]

[0002] Nickel-zinc (NiZn) power ferrite has properties such as high saturation magnetic flux density (Bs), high resistivity (ρ), and low loss (Pcv), and is widely used in a variety of components, such as power transformers, choke coils, pulse wideband transformers, magnetic deflection devices, and sensors. In particular, switching power supply transformer cores manufactured using the properties of NiZn power ferrite, such as high saturation magnetization, high resistivity, and low loss, have become an indispensable element in computers, communications, color televisions, VCRs, office automation, and other electronic devices.

[0003] Higher frequencies are an important feature of power electronics technology. Increasing the operating frequency can reduce the volume and weight of a transformer. At the same magnetic flux density, doubling the frequency can halve the cross-sectional area of ​​the transformer core. For example, the volume of a 6.78MHz, 75W switching power supply is half that of a 13.56MHz, 75W switching power supply, resulting in significant space savings and more efficient use of resources.

[0004] With the application of third-generation semiconductors such as SiC and GaN, wide bandgap materials, in transformers, the transistors in the transformers can operate at frequencies of MHz and above, realizing more efficient power transmission and conversion, and greatly promoting the miniaturization, high frequency, and energy saving of switching power supplies.

[0005] Accordingly, nickel-zinc ferrite core materials used in transformers are also expected to be compatible with the MHz-level operating frequency bands of third-generation semiconductor materials. The optimal application frequency of conventional power ferrites can be raised from several hundred kHz to MHz, which will not only enable the development of ultra-high-efficiency, compact switching power supplies in various consumer electronics fields and improve the efficiency and quality of various electrical devices, but also enable the development of ultra-small, high-efficiency power supplies in the military field that do not require heat dissipation devices, making them suitable for more complex environments, providing higher conversion efficiency, and greatly reducing the burden of transporting equipment.

[0006] More importantly, with the rapid development of new future technology fields such as new energy vehicles, wireless high-power charging, and IoT, high-efficiency, high-density signal and energy conversion and transmission are required, and it is also necessary to avoid other low-frequency interference information. To achieve this, NiZn ferrite materials with ultra-low loss and ultra-high conversion efficiency, especially in the 13.56 MHz frequency band, are required.

[0007] CN105198396A discloses a NiCuZn-based ferrite material and its manufacturing method, which is composed of 47-49 mol% Fe2O3, 15-22 mol% NiO, 25-30 mol% ZnO, 4-7 mol% CuO, and 0.1-0.5 mol% Co2O3. This ferrite material has a high power loss at 13.56 MHz and is not suitable for practical applications.

[0008] CN109095915A discloses a method for the complex substitution of In (Cd, Ga), Ni, Ti, and Co ions to prepare high-performance MnZn ferrite. To a selected main component, a secondary component containing one or more of Ni, Ti, and Co is added; a secondary component containing one or more of In, Cd, and Ga elements is added; and a secondary component containing one or more of Ca and Si elements is added. The use of precious and rare metals increases the manufacturing cost, making it unsuitable for practical production. Summary of the Invention

[0009] The following is a general summary of the subject matter described in detail herein. This summary does not limit the scope of the claims.

[0010] The present application provides a nickel-zinc ferrite material, its preparation method and use, and by adopting a suitable main compound correction process and adding suitable inexpensive correctors and functional additives to the ferrite material, the power loss of the prepared nickel-zinc ferrite material at 13.56 MHz can be significantly reduced.

[0011] In aspect 1, the present application provides: A main material including Fe2O3, Ni2O3, ZnO and CuO, a functional additive including a combination of any three or at least four of Mn3O4, TiO2, Ta2O5, Co2O3 or Sm2O3, and a corrector including Fe2O3 and Ni2O3, A nickel-zinc ferrite material is provided. DETAILED DESCRIPTION OF THE INVENTION

[0012] The raw materials and auxiliary additives in the nickel-zinc ferrite material of the present application can be all commercially available common materials, and do not contain expensive rare metal oxides. Instead, only a few common oxides such as Mn3O4, TiO2, Ta2O5, and Co2O3 are used as additives, which is low cost, allows autonomous control of raw materials, and has low risks. It also optimizes the power loss of the material at 13.56 MHz and improves the power conversion efficiency of the material at 13.56 MHz, and has the advantages of high permeability, high saturation magnetic flux density, and low loss.

[0013] In one embodiment, the molar amount of the main material is taken as 100%, and the molar fraction of Fe2O3 is 47.5 to 49.9%, such as 47.5%, 47.8%, 48%, 49%, or 49.9%.

[0014] In one embodiment, the mole fraction of Ni2O3 is 18.5-22.5%, such as 18.5%, 19%, 19.5%, 20%, 21%, or 22.5%.

[0015] In one embodiment, the mole fraction of ZnO is 21.5 to 25.5%, such as 21.5%, 22%, 23%, 24%, or 25.5%.

[0016] In one embodiment, the mole fraction of CuO is 3.5-7.5%, such as 3.5%, 4%, 5%, 6%, or 7.5%.

[0017] In one embodiment, the amount of Mn3O4 added is 1000 to 1100 ppm, for example, 1000 ppm, 1020 ppm, 1050 ppm, 1080 ppm, or 1100 ppm, based on the total weight of the main material after calcination.

[0018] In one embodiment, the amount of TiO2 added is 0 to 150 ppm, for example, 0 ppm, 10 ppm, 20 ppm, 50 ppm, 100 ppm, or 150 ppm.

[0019] In one embodiment, the amount of Ta2O5 added is 300 to 500 ppm, for example, 300 ppm, 350 ppm, 400 ppm, 480 ppm, or 500 ppm.

[0020] In one embodiment, the amount of Co2O3 added is 1500 to 3500 ppm, for example, 1500 ppm, 1800 ppm, 2000 ppm, 2500 ppm, or 3500 ppm.

[0021] In one embodiment, the amount of Sm2O3 added is 500 to 1200 ppm, for example, 500 ppm, 600 ppm, 800 ppm, 1000 ppm, or 1200 ppm.

[0022] In one embodiment, the amount of Fe2O3 added is 1300 to 2100 ppm, for example, 1300 ppm, 1500 ppm, 1800 ppm, 2000 ppm, or 2100 ppm, based on the total weight of the primary material after calcination.

[0023] In one embodiment, the amount of Ni2O3 added is 1700 to 2300 ppm, for example, 1700 ppm, 1800 ppm, 2000 ppm, 2100 ppm, or 2300 ppm.

[0024] In aspect 2, the present application provides: Step (1) of wet-mixing the main materials to obtain a slurry, drying the slurry, and then calcining the slurry to obtain a powder; (2) mixing the functional additive, the correcting agent and the powder, wet grinding, drying, adding a polyvinyl alcohol solution, and carrying out a granulation process; and step (3) of pressing the material obtained after the granulation process in step (2) and then sintering the material to obtain a nickel-zinc ferrite material. A method for preparing the nickel-zinc ferrite material of embodiment 1 is provided.

[0025] In the relevant material polishing process, whether it is conventional material polishing or the planetary ball milling method used in this application, it is impossible to avoid the increase in the Zr element content in the powder due to the wear of the zirconia balls, which causes an offset in the main composition, making the material's performance in terms of permeability, power loss, temperature characteristics, etc. not meeting the desired design and difficult to control. In this application, the offset in the main composition components caused by the relevant process is manually corrected by adding appropriate amounts of Fe2O3 and Ni2O3, and by adopting an appropriate main composition ratio, combined with an appropriate material polishing process, and adding an appropriate amount of corresponding main composition corrector, the loss at 13.56 MHz of the prepared ferrite material is significantly reduced.

[0026] In one embodiment, the wet mixing described in step (1) comprises wet ball milling.

[0027] In one embodiment, the zirconia balls used for ball milling include zirconia balls of three sizes, Φ6 mm, Φ14 mm, and Φ22 mm, mixed in a ratio of 1:1:1.

[0028] Three sizes available: large, medium and small Zirconia BallBy mixing the zirconia balls, the gaps between the zirconia balls during ball milling can be reduced, which not only enables the raw materials to be mixed uniformly effectively, but also helps to concentrate the size distribution of the raw material particles, avoid component segregation, and improve powder activity.

[0029] In one embodiment, the ball milling comprises planetary ball milling.

[0030] In one embodiment, the ratio of balls to raw materials in the ball milling is 1:(2-4), such as 1:2, 1:2.5, 1:3, 1:3.5, or 1:4.

[0031] The planetary ball milling operation involves two parts, the revolution of the rotating disc and the rotation of the pot in the opposite direction, occurring simultaneously. This includes collisions between balls, milling between balls and pots, and the impact of the balls dropping from a high place to a low place. This allows powders of different particle sizes and hardness to be milled effectively and finely, and has a high ratio of raw material to balls. , different When combined with zirconia balls of different masses, Zirconia Ball The milling can cover the entire pot, and preferably, the direction of revolution and rotation is switched every 10 minutes to mix the powder and Zirconia Ball The movement locus is not in a single direction, so any part of the powder can be milled. Compared to conventional material grinding methods, such as sand milling or ball milling, which have a single direction and a raw material to ball ratio of 1:2~3, planetary ball milling has a higher raw material to ball ratio, making it possible to grind the powder into finer particle sizes in a short time, and making the particle size distribution narrower and more uniform.

[0032] In one embodiment, the temperature of the calcination in step (1) is 850 to 980°C, for example, 850°C, 880°C, 900°C, 950°C, or 980°C.

[0033] In one embodiment, the calcination time is 2.5 to 3.5 hours, such as 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, or 3.5 hours.

[0034] In one embodiment, the calcination is followed by cooling to room temperature in the furnace.

[0035] In one embodiment, the duration of the wet polishing described in step (2) is 90 to 150 minutes, such as 90 minutes, 100 minutes, 120 minutes, 140 minutes, or 150 minutes.

[0036] In one embodiment, the mass concentration of the polyvinyl alcohol solution is 8 to 12% by weight, such as 8%, 9%, 10%, 11%, or 12% by weight.

[0037] In one embodiment, a sieving process is carried out before pressing as described in step (3).

[0038] In one embodiment, the mesh number of the sieve used in the sieving process is 40 to 100 mesh, for example, 40 mesh, 50 mesh, 60 mesh, 80 mesh, or 100 mesh.

[0039] In one embodiment, the density of the material after pressing is ≥ 3.0 g / cm 3 is.

[0040] In one embodiment, the temperature of the sintering treatment described in step (3) is 1050 to 1150°C, such as 1050°C, 1080°C, 1100°C, 1120°C, or 1150°C.

[0041] In one embodiment, the sintering time is 3 to 5 hours, such as 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours.

[0042] In aspect 3, the present application provides: Nickel-zinc ferrite materials are used in new energy automobile, wireless charging or IoT technology fields at 13.56MHz. The present invention provides a use of the nickel-zinc ferrite according to embodiment 1.

[0043] Compared with the related art, the present invention has the following beneficial effects:

[0044] (1) The present invention adopts a suitable main compounding correction process and adds a suitable correction agent to the ferrite material, which can significantly reduce the power loss of the prepared nickel-zinc ferrite material at 13.56 MHz.

[0045] (2) The initial magnetic permeability of the nickel-zinc ferrite according to the present invention is within the range of 100±25%, the saturation magnetic flux density is 420 mT or more at 25°C, the saturation magnetic flux density is 360 mT or more at 100°C, and the core loss is 346 kW / m at 13.56 MHz and 30 mT / 25°C. 3 The core loss at 20mT / 25℃ is 279kW / m 3 At 30mT / 100℃, the core loss is 436kW / m 3 The core loss at 20mT / 100℃ is 388kW / m 3 The following can be achieved:

[0046] Other aspects may be appreciated upon reading and understanding the detailed description. [Example]

[0047] The technical solution of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the following examples are only for understanding the present application and should not be considered as specifically limiting the present application.

[0048] Example 1 This example provides a nickel-zinc ferrite material, whose main material composition is ZnO: 23.5 mol%, Fe2O3: 49.5 mol%, Ni2O3: 20.5 mol%, CuO: 6.5 mol%. The nickel-zinc ferrite material is prepared by the following method.

[0049] (1) Four raw materials, Fe2O3, Ni2O3, ZnO, and CuO, were weighed and mixed in the above-mentioned ratio, and then mixed using a wet ball mill. Three sizes of zirconia balls, Φ6 mm, Φ14 mm, and Φ22 mm, were used to mix the materials in a ratio of 1:1:1, so that the ratio of raw materials to balls was 1:3. A slurry was obtained, dried, and calcined in an air atmosphere at 950°C, kept at that temperature for 3 hours. The slurry was then cooled to room temperature in a furnace to obtain a powder.

[0050] (2) Step (1) After calcination, the auxiliary functional additives Mn3O4, TiO2, Ta2O5, Co2O3 and the main compounding additives Fe2O3, Ni2O3 were weighed and mixed into the powder to obtain the doped powder. Here, the mixing ratio is determined by the weight ratio of the weighed step. (1) Based on the weight of the powder obtained in step 1, the contents were 1050 ppm Mn3O4, 100 ppm TiO2, 400 ppm Ta2O5, 2500 ppm Co2O3, 1700 ppm Fe2O3, and 2000 ppm Ni2O3. The obtained material was placed in a planetary ball mill and wet-milled for 120 minutes. The zirconia balls were of two sizes, Φ4 mm and Φ5 mm. Zirconia Ball The powder was mixed at a ratio of 1:1, with a ratio of raw material to balls of 1:7. A slurry was obtained, dried, and then a 10 wt% polyvinyl alcohol (PVA) solution was added. The mixture was mixed in a mortar and then pre-pressed into a disk shape using a press, allowing the polyvinyl alcohol (PVA) solution and the dried powder to be thoroughly and uniformly mixed.

[0051] (3) The obtained powder is sieved through an 80-mesh sieve to obtain a powder with a density of 3.0 g / cm or more. 3 The resulting green body was pressed into a solid ring-shaped green body, and the resulting green body was sintered in a bell jar type air sintering furnace at a sintering temperature of 1040°C and a heat retention time of 4 hours to obtain a nickel-zinc ferrite material.

[0052] Example 2 The difference between this example and Example 1 is that the contents of Fe2O3, Ni2O3, and CuO used are 49 mol%, 22.5 mol%, and 5 mol%, respectively. Since changes in the contents of Fe2O3 and ZnO in the main composition directly affect the temperature characteristics of the material, an offset occurs in the optimum performance temperature range of the material. Therefore, in order to keep the optimum performance temperature range always within the range of 25 to 100°C, it is necessary to adjust the doping amount of Co2O3 additive, which has a similar modifying effect, depending on the example. Therefore, the amount of cobalt added was changed to 2500 ppm. Other conditions and parameters were exactly the same as those of Example 1.

[0053] Example 3 The difference between this example and Example 1 is that the contents of Fe2O3, Ni2O3, and CuO used are 47.5 mol%, 22.0 mol%, and 7 mol%, respectively. Since changes in the contents of Fe2O3 and ZnO in the main composition directly affect the temperature characteristics of the material, an offset occurs in the optimum performance temperature range of the material. Therefore, in order to keep the optimum performance temperature range always within the range of 25 to 100°C, it is necessary to adjust the doping amount of Co2O3 additive, which has a similar modifying effect, according to the example. Therefore, the amount of cobalt added was changed to 1500 ppm. Other conditions and parameters were exactly the same as those of Example 1.

[0054] Example 4 The difference between this example and Example 1 is that the contents of Fe2O3, Ni2O3, ZnO, and CuO used are 49.5 mol%, 18.6 mol%, 25.5 mol%, and 6.4 mol%, respectively. Since changes in the contents of Fe2O3 and ZnO in the main composition directly affect the temperature characteristics of the material, an offset occurs in the optimum performance temperature range of the material. In order to ensure that the optimum performance temperature range is always within the range of 25 to 100°C, the doping amount of Co2O3 additive, which has a similar modifying effect, needs to be adjusted according to the example. Therefore, the doping amount of cobalt was changed to 3000 ppm. Other conditions and parameters were exactly the same as those of Example 1.

[0055] Example 5 The difference between this example and Example 1 is that the contents of Fe2O3, Ni2O3, ZnO, and CuO used are 49.9 mol%, 22.5 mol%, 21.5 mol%, and 6.1 mol%, respectively. Since changes in the contents of Fe2O3 and ZnO in the main composition directly affect the temperature characteristics of the material, an offset occurs in the optimum performance temperature range of the material. In order to ensure that the optimum performance temperature range is always within the range of 25 to 100°C, the doping amount of Co2O3 additive, which has a similar modifying effect, needs to be adjusted according to the example. Therefore, the doping amount of cobalt was changed to 2000 ppm. Other conditions and parameters were exactly the same as those of Example 1.

[0056] Example 6 This embodiment and Example 1 The difference between the two is that the wet ball milling time described in step (2) was 90 min, and the wear of the zirconia balls was zirconium was less than that in Example 2, and the amounts of the main compounding correctors Fe2O3 and Ni2O3 were 1300 ppm and 1700 ppm, respectively; other conditions and parameters were exactly the same as in Example 1.

[0057] Example 7 This embodiment and Example 1 The difference between the two is that the wet ball milling time described in step (2) was 150 min, and the wear of the zirconia balls was zirconium was less than that in Example 2, and the amounts of the main compounding correctors Fe2O3 and Ni2O3 were 2100 ppm and 2300 ppm, respectively; other conditions and parameters were exactly the same as in Example 1.

[0058] Example 8 The only difference between this example and Example 2 is that the wet ball milling described in step (2) was replaced with conventional sand milling, and other conditions and parameters were Example 2 It was exactly the same.

[0059] Comparative Example 1 The only difference between this comparative example and Example 2 is that no correction agent was added, and other conditions and parameters were Example 2 It was exactly the same.

[0060] Comparative Example 2 The only difference between this comparative example and Example 2 is that one correcting agent, Fe2O3, was added, and the other conditions and parameters were Example 2 It was exactly the same.

[0061] Comparative Example 3 The only difference between this comparative example and Example 2 is that one kind of correction agent, Ni2O3, was added, and other conditions and parameters were Example 2 It was exactly the same.

[0062] Comparative Example 4 The only difference between this comparative example and Example 2 is that no functional additive was added, and other conditions and parameters were Example 2 It was exactly the same.

[0063] Comparative Example 5 The difference between this comparative example and Example 2 is that only two functional additives, Mn3O4 and Co2O3, were added, and other conditions and parameters were Example 2 It was exactly the same.

[0064] Performance Test: For the samples obtained in Examples 1 to 7 and Comparative Examples 1 and 2, the real permeability was measured at 1 KHz / 0.25 V, and the magnetic flux density at 25 and 100°C was measured, respectively. The loss per unit volume Pcv was measured using a Japan Iwasaki SY8218 BH measuring instrument. In addition, the initial permeability and core loss at 30 mT of the samples obtained in Example 8 and Comparative Examples 1 to 5 were selectively measured, and the measurement results are shown in Table 1.

[0065] [Table 1]

[0066] As can be seen from Table 1, in Examples 1 to 7, the initial magnetic permeability of the nickel-zinc ferrite according to the present invention is within the range of 100±25%, the saturation magnetic flux density is ≧420 mT at 25°C, the saturation magnetic flux density is ≧360 mT at 100°C, and the core loss at 13.56 MHz, 30 mT / 25°C is 346 kW / m 3 At 20mT / 25℃, the core loss is 279kW / m 3 At 30mT / 100℃, the core loss is 436kW / m 3 At 20mT / 100℃, the core loss is 388kW / m 3 It has been found that the following can be achieved:

[0067] By comparing Example 1 with Examples 6 to 7, it is found that the present invention can adjust the amount of correcting agent added by ball milling time, the method is flexible and controllable, and the effect is very significant.

[0068] A comparison between Example 2 and Example 8 shows that in the process of preparing nickel-zinc ferrite according to the present invention, the influence of the grinding method on the prepared ferrite is very significant. When conventional sand milling is used instead of planetary ball milling as ball milling, there are obvious deficiencies in both loss and permeability performance. However, the present invention uses planetary ball milling with a high ratio of raw material to balls, which allows the powder particle size to be finely ground in a short time, making the particle size distribution narrower and more uniform.

[0069] By comparing Example 2 with Comparative Examples 1 to 3, it was found that without the addition of Fe2O3 and / or Ni2O3, the temperature characteristics of the loss of the prepared nickel-zinc ferrite material changed, resulting in increased losses at 25°C and 100°C. The present invention employs an appropriate main compounding correction process, which can significantly reduce the power loss at 13.56MHz.

[0070] By comparing Example 2 with Comparative Examples 4 and 5, the present application has found that adding a number of functional additives to the nickel-zinc ferrite material, among which adding an appropriate amount of Mn3O4, can significantly increase the resistivity and improve the power consumption characteristics, and adding an appropriate amount of TiO2 can significantly increase the resistivity and improve the power consumption characteristics. 2+ The contribution of Co2O3 to the conductive mechanism can be suppressed, reducing material loss, and the sintering temperature can be reduced without promoting grain growth, improving the overall magnetic properties. Adding a small amount of Co2O3 can improve the frequency and loss characteristics of the material, among which, Co 2+ It has been found that by adding an appropriate amount of Sm2O3, the magnetostriction coefficient of the material can be effectively controlled, and by adding an appropriate amount of Ta2O5, the temperature curve can be made flatter.

[0071] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto, and the applicant declares that it should be understood that any modifications or replacements that a person skilled in the art can easily conceive within the technical scope disclosed in the present application are all included in the scope of protection and disclosure of the present application.

Claims

1. Fe ２ O ３ , Ni ２ O ３ , ZnO and CuO, and a main material including Mn ３ O ４ , TiO ２ , Ta ２ O ５ , Co ２ O ３ or Sm ２ O ３ A functional additive comprising a combination of any three or at least four of the above, and Fe ２ O ３ and Ni ２ O ３ and a corrector comprising: Nickel-zinc ferrite material.

2. The molar amount of the main material is 100%, and the Fe ２ O ３ The mole fraction of is 47.5 to 49.9%. The nickel-zinc ferrite material of claim 1 .

3. The molar amount of the main material is 100%, and the Ni ２ O ３ The mole fraction of is 18.5 to 22.5%. The nickel-zinc ferrite material according to claim 1 or 2.

4. The molar fraction of the ZnO is 21.5 to 25.5% when the molar amount of the main material is 100%. The nickel-zinc ferrite material according to any one of claims 1 to 3.

5. The molar fraction of CuO is 3.5 to 7.5%. The nickel-zinc ferrite material according to any one of claims 1 to 4.

6. The total weight of the main material after calcination is ３ O ４ The amount of addition is 1000 to 1100 ppm, Preferably, the TiO ２ The amount of addition is 0 to 150 ppm, Preferably, the Ta ２ O ５ The amount of addition is 300 to 500 ppm, Preferably, the Co ２ O ３ The amount of addition is 1500 to 3500 ppm, Preferably, the Sm ２ O ３ The amount of addition is 500 to 1200 ppm. The nickel-zinc ferrite material according to any one of claims 1 to 5.

7. The total weight of the main material after calcination is ２ O ３ The amount of addition is 1300 to 2100 ppm, Preferably, the Ni ２ O ３ The amount of addition is 1700 to 2300 ppm. The nickel-zinc ferrite material according to any one of claims 1 to 6.

8. A method for preparing the nickel-zinc ferrite material according to any one of claims 1 to 7, comprising the steps of: Step (1) of wet-mixing main materials to obtain a slurry, drying the slurry, and then calcining the slurry to obtain a powder; (2) mixing the functional additive, the correcting agent and the powder, wet grinding, drying, adding a polyvinyl alcohol solution, and carrying out a granulation process; Step (3) of pressing the material obtained after the granulation process described in step (2) and then sintering the material to obtain the nickel-zinc ferrite material; A preparation method comprising:

9. The wet mixing described in step (1) comprises wet ball milling. The preparation method according to claim 8.

10. The zirconia balls used in the ball milling include zirconia balls of three sizes, Φ6 mm, Φ14 mm, and Φ22 mm, mixed in a ratio of 1:1:1, Preferably, the ball milling comprises planetary ball milling; Preferably, the ratio of balls to raw materials in the ball milling is 1: (2-4).

10. The preparation method according to claim 9.

11. The temperature of the calcination described in step (1) is 850 to 980°C, Preferably, the calcination time is 2.5 to 3.5 hours, Preferably, the calcination is followed by cooling to room temperature in the furnace. The preparation method according to any one of claims 8 to 10.

12. The wet polishing time described in step (2) is 90 to 150 minutes; Preferably, the mass concentration of the polyvinyl alcohol solution is 8 to 12% by weight. The preparation method according to any one of claims 8 to 11.

13. Sieving is performed before pressing as described in step (3), Preferably, the mesh number of the sieve used in the sieving process is 40 to 100 mesh, Preferably, the density of the material after pressing is ≥ 3.0 g / cm ３ That is, The preparation method according to any one of claims 8 to 12.

14. The sintering temperature is 1050 to 1150°C, Preferably, the sintering process lasts for 3 to 5 hours. The preparation method according to any one of claims 8 to 13.

15. Use of the nickel zinc ferrite material according to any one of claims 1 to 7, The nickel-zinc ferrite material is used in the fields of new energy automobiles, wireless charging or IoT technology at 13.56MHz.

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