阅读说明：本技术 一种NFC用低损耗NiCuZn软磁铁氧体材料及其制备方法和应用 (Low-loss NiCuZn soft magnetic ferrite material for NFC and preparation method and application thereof ) 是由 刘明 马春蕊 胡天翼 于 2021-08-27 设计创作，主要内容包括：本发明公开了一种NFC用低损耗NiCuZn软磁铁氧体材料及其制备方法和应用,本发明NFC用低损耗NiCuZn软磁铁氧体材料,包括主成分和辅助成分,其中,以重量百分比计,主成分包括：Fe-(2)O-(3):64.14wt％～65wt％,ZnO:14.22wt％～24.5wt％,NiO:7.64％～17.34wt％,余量为CuO；辅助成分包括V-(2)O-(5)和Co-(2)O-(3),以重量百分比计,V-(2)O-(5)的含量为主成分的0.4wt％,Co-(2)O-(3)的含量为主成分的0.4wt％～0.8wt％。本发明的材料能在工作频率下稳定工作,其磁导率实部(μ′)为60～150同时虚部(μ″)小于3,满足NFC的使用要求。(The invention discloses a low-loss NiCuZn soft magnetic ferrite material for NFC, and a preparation method and application thereof, and the low-loss NiCuZn soft magnetic ferrite material for NFC comprises main components and auxiliary components, wherein the main components comprise, by weight: fe 2 O 3 64.14 to 65 weight percent of ZnO, 14.22 to 24.5 weight percent of ZnO, 7.64 to 17.34 weight percent of NiO and the balance of CuO; the auxiliary component comprises V 2 O 5 And Co 2 O 3 In weight percent, V 2 O 5 Is 0.4 wt% of the main component, Co 2 O 3 The content of (A) is 0.4 wt% -0.8 wt% of the main component. The material can stably work under the working frequency, the real part (mu ') of the magnetic conductivity of the material is 60-150, and the imaginary part (mu') is less than 3, so that the use requirement of NFC is met。)

1. A low-loss NiCuZn soft magnetic ferrite material for NFC is characterized by comprising a main component and an auxiliary component, wherein the main component comprises the following components in percentage by weight: fe₂O₃63 to 65 weight percent of ZnO, 13 to 25 weight percent of NiO, 7 to 18 weight percent of NiO and the balance of CuO;

the auxiliary component comprises V₂O₅And Co₂O₃In weight percent, V₂O₅The content of (A) is 0.2 wt% -0.4 wt% of the main component, Co₂O₃The content of (A) is 0.4 wt% -0.8 wt% of the main component.

2. The low-loss NiCuZn soft magnetic ferrite material for NFC according to claim 1, wherein the real part of the permeability of the low-loss NiCuZn soft magnetic ferrite material for NFC is 60-150 and the imaginary part of the permeability of the low-loss NiCuZn soft magnetic ferrite material for NFC is less than 3 at the application frequency of NFC.

3. The low-loss NiCuZn soft magnetic ferrite material for NFC according to claim 1 or 2, wherein the application frequency of the low-loss NiCuZn soft magnetic ferrite material for NFC is 13.56 MHz.

4. A preparation method of a low-loss NiCuZn soft magnetic ferrite material for NFC is characterized by comprising the following steps:

carrying out ball milling and mixing on main component raw materials of the low-loss NiCuZn soft magnetic ferrite material for NFC to obtain a mixture A;

pre-sintering the mixture A at high temperature;

mixing the mixture A subjected to high-temperature pre-sintering with auxiliary components of a low-loss NiCuZn soft magnetic ferrite material for NFC to obtain a mixture B;

performing ball milling, granulation and molding on the mixture B to obtain a sample blank;

performing high-temperature gradient sintering on the sample blank, naturally cooling to room temperature to obtain the low-loss NiCuZn soft magnetic ferrite material for NFC, wherein the sintering temperature is 940-;

the main components of the low-loss NiCuZn soft magnetic ferrite material for NFC comprise, by weight: fe₂O₃63 to 65 weight percent of ZnO, 13 to 25 weight percent of NiO, 7 to 18 weight percent of NiO and the balance of CuO;

the auxiliary component of the low-loss NiCuZn soft magnetic ferrite material for NFC comprises V₂O₅And Co₂O₃In weight percent, V₂O₅The content of (A) is 0.2 wt% -0.4 wt% of the main component, Co₂O₃The content of (A) is 0.4 wt% -0.8 wt% of the main component.

5. The preparation method of the low-loss NiCuZn soft magnetic ferrite material for NFC according to claim 4, wherein when the main component raw materials of the low-loss NiCuZn soft magnetic ferrite material for NFC are subjected to ball milling and mixing to obtain a mixture A, distilled water is added into the main component raw materials, zirconium balls are adopted for ball milling, the ball milling speed is 400 +/-5 revolutions per minute, and the ball milling time is 6 +/-0.1 h.

6. The preparation method of the low-loss NiCuZn soft magnetic ferrite material for NFC according to claim 4, characterized in that when the mixture A is presintered at high temperature, the mixture A is dried, then the dried mixture A is heated to 700 ℃ -800 ℃ at a heating rate of 1.5 +/-0.5 ℃/min, the temperature is kept for 2 +/-0.1 h, the mixture A is taken out of a furnace after being cooled to room temperature along with the furnace, and the high-temperature presintering is completed.

7. The preparation method of the low-loss NiCuZn soft magnetic ferrite material for NFC according to claim 4, characterized in that the mixture A after high-temperature pre-sintering is mixed with auxiliary components of the low-loss NiCuZn soft magnetic ferrite material for NFC to obtain a mixture B, the mixture A after high-temperature pre-sintering is firstly crushed, and then the auxiliary components are added to obtain the mixture B.

8. The preparation method of the low-loss NiCuZn soft magnetic ferrite material for NFC according to the claim 4, characterized in that when the mixture B is ball-milled, the mixture B and distilled water are mixed according to the mass ratio of (2 +/-0.1) to 1 to (1 +/-0.1), and the mixture B is ball-milled for 8 +/-0.1 h at the rotating speed of 400 +/-5 r/min;

and when the mixture B is granulated and molded, drying the ball-milled slurry, adding 6-8 wt% of polyvinyl alcohol solution for granulation, screening the manufactured spherical particles, taking the spherical particles with 60-120 meshes, and cold-pressing the taken spherical particles with 60-120 meshes at 4-6 MPa to form a sample blank.

9. The preparation method of the low-loss NiCuZn soft magnetic ferrite material for NFC according to claim 4, characterized in that when the sample blank is sintered at high temperature gradient, the sample blank is heated to 450 plus or minus 20 ℃ at a rate of 1.5 plus or minus 0.5 ℃/min, and then the temperature is kept for 2 h; then raising the temperature to 900 plus or minus 20 ℃ at the speed of 2.5 plus or minus 0.5 ℃/min, finally raising the temperature to the sintering temperature at the speed of 1.5 plus or minus 0.5 ℃/min, and carrying out heat preservation for 4 plus or minus 0.1 h.

10. Use of a low loss NiCuZn soft magnetic ferrite material for NFC according to any of the claims 1 to 3 in NFC.

Technical Field

The invention relates to the technical field of soft magnetic ferrite materials, in particular to a low-loss NiCuZn soft magnetic ferrite material for NFC and a preparation method and application thereof.

Background

Nfc (near field communication), which is a new wireless communication technology emerging in recent years, is widely applied to various mobile phone payments, entrance guards, public transportation cards, and the like, and is mainly applied to 13.56MHz and a working distance of 10 cm. The built-in NFC antenna can generate a magnetic field generated by eddy current under the metal environment inside the mobile phone to cause the failure of signal attenuation and card reading, and the method for solving the problem at present is to add a layer of ferrite magnetic sheet with high magnetic conductivity and low loss on a circuit board to ensure the normal work of the antenna. For NiCuZn ferrites for NFC, as large a real permeability part as possible and as small an imaginary permeability part (loss) as possible are required. Generally, the increase of the real part of the magnetic permeability also leads to the increase of the imaginary part (loss) of the magnetic permeability, and in addition, under the influence of crystal growth, small crystal grains are easy to generate large loss at a low sintering temperature, and a high sintering temperature is easy to bend and deform the ferrite magnetic sheet and consumes more energy at the high sintering temperature. Therefore, the NiCuZn soft magnetic ferrite material with the characteristics of low sintering temperature and low loss can be more advantageously applied to the NFC antenna module, and meanwhile, considering the practicability, whether the raw material is harmful or not is still important.

CN 104496451A discloses a NiCuZn ferrite material with high magnetic permeability and low magnetic loss and a preparation method thereof, the raw material consists of a main component and an auxiliary component, the main component is Fe₂O₃ZnO, CuO and NiO, wherein Fe₂O₃The mol percentages of ZnO and CuO in the main component are respectively 48.5-50.0 mol%, 20-25 mol%, 10-12 mol%, and the balance of NiO; the additive comprises 0.6-1.0 wt% of Co as the main component₂O₃And LiF in an amount of 0.1 to 0.5 wt% based on the main component. The real parts of the magnetic permeability of the invention are all larger than 200, while the imaginary parts are all larger than 3 and can not be further optimized.

Proposed in the article of microstructure and electromagnetic property of Bi substituted NiCuZn ferrite published by magnetic materials and devices by the national key laboratory of Wu Xiaohu et al, university of electronic technology and Integrated devices in 2012, is Ni_0.24Cu_0.21Zn_0.55Fe₂O₄Incorporating 3 wt% of Bi₂O₃When the sample obtained after sintering at 900 ℃ for 3 hours has a μ' (real part of magnetic permeability) of about 170 at a frequency of 13.56MHz, the imaginary part of magnetic permeability is very high, about 40.

In the above-mentioned patent and literature, although the magnetic permeability is high and the sintering temperature is low, the loss of the sample is too large in the above studies, which cannot fully satisfy the requirement of NFC on soft magnetic materials.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a low-loss NiCuZn soft magnetic ferrite material for NFC and a preparation method and application thereof.

The technical scheme adopted by the invention is as follows:

a low-loss NiCuZn soft magnetic ferrite material for NFC comprises a main component and an auxiliary component, wherein the main component comprises the following components in percentage by weight: fe₂O₃63 to 65 weight percent of ZnO, 13 to 25 weight percent of NiO, 7 to 18 weight percent of NiO and the balance of CuO;

the auxiliary component comprises V₂O₅And Co₂O₃In weight percent, V₂O₅The content of (A) is 0.2 wt% -0.4 wt% of the main component, Co₂O₃The content of (A) is 0.4 wt% -0.8 wt% of the main component.

Preferably, under the application frequency of NFC, the real part of the permeability of the low-loss NiCuZn soft magnetic ferrite material for NFC is 60-150, and the imaginary part of the permeability is less than 3.

Preferably, the application frequency of the low-loss NiCuZn soft magnetic ferrite material for NFC is 13.56 MHz.

The invention also provides a preparation method of the low-loss NiCuZn soft magnetic ferrite material for NFC, which comprises the following steps:

carrying out ball milling and mixing on main component raw materials of the low-loss NiCuZn soft magnetic ferrite material for NFC to obtain a mixture A;

pre-sintering the mixture A at high temperature;

mixing the mixture A subjected to high-temperature pre-sintering with auxiliary components of a low-loss NiCuZn soft magnetic ferrite material for NFC to obtain a mixture B;

performing ball milling, granulation and molding on the mixture B to obtain a sample blank;

performing high-temperature gradient sintering on the sample blank, naturally cooling to room temperature to obtain the low-loss NiCuZn soft magnetic ferrite material for NFC, wherein the sintering temperature is 940-;

the main components of the low-loss NiCuZn soft magnetic ferrite material for NFC comprise, by weight: fe₂O₃63 to 65 weight percent of ZnO, 13 to 25 weight percent of NiO, 7 to 18 weight percent of NiO and the balance of CuO;

the auxiliary component of the low-loss NiCuZn soft magnetic ferrite material for NFC comprises V₂O₅And Co₂O₃In weight percent, V₂O₅The content of (A) is 0.2 wt% -0.4 wt% of the main component, Co₂O₃The content of (A) is 0.4 wt% -0.8 wt% of the main component.

Preferably, when the main component raw materials of the low-loss NiCuZn soft magnetic ferrite material for NFC are subjected to ball milling and mixing to obtain a mixture A, distilled water is added into the main component raw materials, zirconium balls are used for ball milling, the ball milling rotating speed is 400 +/-5 revolutions per minute, and the ball milling time is 6 +/-0.1 h.

Preferably, when the mixture A is presintered at high temperature, the mixture A is dried, then the dried mixture A is heated to 700-800 ℃ at the heating rate of 2 +/-0.5 ℃/min, the temperature is kept for 2 +/-0.1 h, the mixture A is cooled to room temperature along with a furnace and then taken out of the furnace, and the presintering at high temperature is completed.

Preferably, when the mixture A subjected to high-temperature pre-sintering is mixed with auxiliary components of a low-loss NiCuZn soft magnetic ferrite material for NFC to obtain a mixture B, the mixture A subjected to high-temperature pre-sintering is crushed, and then the auxiliary components are added to obtain the mixture B.

Preferably, when the mixture B is ball-milled, the mixture B and distilled water are mixed according to the mass ratio of (2 +/-0.1) to 1 to (1 +/-0.1), and the mixture B is ball-milled for 8 hours at the rotating speed of 400 +/-5 revolutions per minute;

and when the mixture B is granulated and molded, drying the ball-milled slurry, adding 6-8 wt% of polyvinyl alcohol solution for granulation, screening the manufactured spherical particles, taking the spherical particles with 60-120 meshes, and cold-pressing the taken spherical particles with 60-120 meshes at 4-6 MPa to form a sample blank.

Preferably, when the sample blank is subjected to high-temperature gradient sintering, the sample blank is heated to 450 +/-20 ℃ at the speed of 1.5 +/-0.5 ℃/min, and then the temperature is kept for 2 hours; then raising the temperature to 900 plus or minus 20 ℃ at the speed of 2.5 plus or minus 0.5 ℃/min, finally raising the temperature to the sintering temperature at the speed of 1.5 plus or minus 0.5 ℃/min, and preserving the temperature for 4 plus or minus 0.1 h.

The invention applies the low-loss NiCuZn soft magnetic ferrite material for NFC in NFC.

The invention has the following beneficial effects:

the invention discloses a low-loss NiCuZn soft magnetic ferrite material for NFC, which comprises a main component and an auxiliary component, wherein the main component comprises the following components in percentage by weight: fe₂O₃63 to 65 weight percent of ZnO, 13 to 25 weight percent of NiO, 7 to 18 weight percent of NiO and the balance of CuO; in the range, the Ni/Zn ratio of the main formula can be adjusted, so that the NiCuZn soft magnetic ferrite material has relatively low eddy current loss at 13.56MHz and simultaneously has different magnetic permeability. In addition, the CuO is used for replacing part of NiO, and some trace elements are added, such as: v₂O₅、Co₂O₃So that the sintering temperature of the product is obviously reduced and the sintering density is obviously increased. The loss characteristic is obviously improved, and the low loss requirement of NFC can be met by obtaining a tiny imaginary part numerical value (less than 3).

Drawings

Fig. 1(a) -fig. 1(e) are the real part and imaginary part of the permeability spectra of the samples of the low-loss NiCuZn soft magnetic ferrite for NFC prepared in examples 1-4 in the range of 1 MHz-40 MHz, respectively.

Detailed Description

The invention is further described with reference to the following drawings and examples.

The raw materials of the low-loss NiCuZn soft magnetic ferrite material for NFC comprise main components and auxiliary components, wherein the main components comprise the following oxides in percentage by weight: fe₂O₃:63wt％～65wt％，13 to 25 weight percent of ZnO, 7 to 18 weight percent of NiO and the balance of CuO; the auxiliary component comprises V₂O₅And Co₂O₃In weight percent, V₂O₅The content of (A) is 0.3 wt% -0.5 wt% of the main component, Co₂O₃The content of (A) is 0.4 wt% -0.8 wt% of the main component.

The preparation method of the low-loss NiCuZn soft magnetic ferrite material for NFC comprises the following steps:

the method comprises the following steps: mixing raw materials: mixing the main components;

step two: carrying out primary planetary ball milling on the main component raw materials: the main component raw materials are put into a ball milling tank of a planetary ball mill, and a certain amount of zirconium balls and distilled water are added according to the mass ratio: distilled water: raw materials (2 ± 0.1):1: (1 +/-0.1) and ball-milling for 6h +/-0.1 at the rotating speed of 400 +/-5 revolutions per minute to obtain the slurry of the main component.

Step three: high-temperature pre-sintering: drying the main component slurry obtained in the second step in a drying oven, pre-sintering the obtained powder, raising the temperature to 700-800 ℃ at a heating rate of 2 +/-0.5 ℃/min from room temperature, preserving the heat for 2 +/-0.1 h, cooling to room temperature along with the furnace, and discharging;

step four: doping trace elements: performing wheel grinding and crushing treatment on the powder subjected to high-temperature pre-sintering in the third step, and then adding auxiliary components;

step five: secondary planetary ball milling: putting the ingredients obtained in the fourth step into a ball milling tank of a planetary ball mill, mixing the ingredients according to the mass ratio of the milling balls to distilled water (2 +/-0.1) to 1 (1 +/-0.1), ball milling for 8 +/-0.1 h at the rotating speed of 400 +/-5 revolutions per minute, and drying the milled slurry in a drying oven;

step six: granulating and forming: adding a polyvinyl alcohol (PVA) solution into the powder prepared in the fifth step according to 6-8 wt% of the material weight for granulation, screening the manufactured spherical particles by using 60-mesh and 120-mesh screens, taking the powder between the 60-mesh and 120-mesh screens, and carrying out cold press molding on the powder into a sample ring blank body by using a 30T full-automatic powder molding machine, wherein the molding pressure is 4-6 MPa;

step seven: high-temperature gradient sintering: and (3) placing the sample ring blank formed in the step six into a box type electric furnace for high-temperature sintering, wherein the temperature rise gradient is as follows: heating at the room temperature of 450 +/-20 ℃ at the rate of 1.5 +/-0.5 ℃/min, preserving the heat at the temperature of 450 +/-20 ℃ for 2 +/-0.1 h, then heating from the temperature of 450 +/-20 ℃ to the temperature of 900 +/-20 ℃ at the rate of 2.5 +/-0.5 ℃/min, finally heating to the sintering temperature at the rate of 1.5 +/-0.5 ℃/min, preserving the heat for 4.0 +/-0.1 h, naturally cooling to room temperature, and discharging; and finishing all the procedures to obtain the test sample ring made of the low-loss NiCuZn soft magnetic ferrite material for NFC.

Example 1:

the preparation process of the low-loss NiCuZn soft magnetic ferrite material for NFC comprises the following steps:

the method comprises the following steps: mixing the raw materials, and respectively taking Fe according to mass percentage₂O₃65.00 wt% of Fe, 13.00 wt% of ZnO, 18.00 wt% of NiO and the balance of CuO₂O₃The total content of ZnO, NiO and CuO is 100 wt%; (ii) a

Step two: and (2) performing primary planetary ball milling, namely filling the ingredients obtained in the step one into a planetary ball mill ball milling tank, and filling zirconium balls and distilled water, wherein the zirconium balls: distilled water: raw materials are 2: 1: 1, ball milling for 6 hours at the rotating speed of 400 +/-5 revolutions per minute to obtain the slurry of the main component.

Step three: pre-burning at high temperature, namely pre-burning the powder obtained by drying the main component slurry obtained in the step two in a drying box, raising the temperature to 750 ℃ at the heating rate of 2 ℃/min from room temperature, preserving the temperature for 2h, cooling to room temperature along with the furnace, and discharging;

step four: doping trace elements, grinding and crushing the powder subjected to the pre-sintering in the third step, and adding V₂O₅And Co₂O₃，V₂O₅Is 0.2 wt% of the main component, Co₂O₃The content of (B) is 0.4 wt% of the main component;

step five: and (3) performing secondary planetary ball milling, namely filling the ingredients obtained in the step four into a planetary ball mill, and mixing the ingredients according to the following ratio: distilled water: raw materials are 2: 1: 1, ball-milling for 8 hours at a rotating speed of 400 +/-5 revolutions per minute, and drying the milled slurry in a drying oven;

step six: granulating and molding, namely adding a polyvinyl alcohol (PVA) solution into the powder prepared in the fifth step according to 7 wt% of the material weight for granulation, screening the manufactured spherical particles by using 60-mesh and 120-mesh screens, taking the powder between the 60-mesh and 120-mesh screens, and performing cold press molding on the powder into a sample ring blank body by using a 30T full-automatic powder molding machine, wherein the molding pressure is 6 MPa;

step seven: and (3) high-temperature gradient sintering, namely putting the sample blank formed in the step six into a box type electric furnace for high-temperature sintering, wherein the temperature rise gradient is as follows: raising the temperature from room temperature to 450 ℃ at the speed of 1.5 ℃/min, preserving the heat at 450 ℃ for 2h, then raising the temperature from 450 ℃ to 900 ℃ at the speed of 2.5 ℃/min, finally raising the temperature to the sintering temperature at the speed of 1.5 ℃/min, preserving the heat for 4.0h, naturally cooling to room temperature, and discharging; and finishing all the working procedures.

Example 2:

the preparation process of the low-loss NiCuZn soft magnetic ferrite material for NFC comprises the following steps:

the method comprises the following steps: mixing the raw materials, and respectively taking Fe according to mass percentage₂O₃65.00 wt% of Fe, 13.00 wt% of ZnO, 18.00 wt% of NiO and the balance of CuO₂O₃The total content of ZnO, NiO and CuO is 100 wt%;

step two: and (2) performing primary planetary ball milling, namely loading the ingredients obtained in the step one into a planetary ball mill, mixing the ingredients according to the mass ratio of grinding balls to materials to distilled water of 2: 1, loading zirconium balls and distilled water into the planetary ball mill, and performing ball milling for 6.1h at the rotating speed of 400 +/-5 revolutions per minute to obtain the slurry of the main component.

Step three: pre-burning at high temperature, namely pre-burning the powder obtained by drying the main component slurry obtained in the step two in a drying box, heating to 800 ℃ from room temperature at the heating rate of 2.1 ℃/min, preserving heat for 2.1h, cooling to room temperature along with the furnace, and discharging;

step four: doping trace elements, grinding and crushing the powder subjected to the pre-sintering in the third step, and adding V₂O₅And Co₂O₃，V₂O₅Is 0.4 wt% of the main component, Co₂O₃The content of (B) is 0.4 wt% of the main component;

step five: performing secondary planetary ball milling, namely loading the ingredients obtained in the fourth step into a planetary ball mill, mixing the ingredients according to the mass ratio of grinding balls to the ingredients to distilled water of 2.1: 1: 0.9, performing ball milling for 7.9h at the rotating speed of 400 +/-5 revolutions per minute, and drying the milled slurry in a drying oven;

step six: granulating and molding, namely adding a polyvinyl alcohol (PVA) solution into the powder prepared in the fifth step according to 7 wt% of the material weight for granulation, screening the manufactured spherical particles by using 60-mesh and 120-mesh screens, taking the powder between the 60-mesh and 120-mesh screens, and performing cold press molding on the powder into a sample ring blank body by using a 30T full-automatic powder molding machine, wherein the molding pressure is 6 MPa;

step seven: and (3) high-temperature gradient sintering, namely putting the sample blank formed in the step six into a box type electric furnace for high-temperature sintering, wherein the temperature rise gradient is as follows: raising the temperature from room temperature to 470 ℃ at the speed of 1.0 ℃/min, preserving the heat at 470 ℃ for 2h, then raising the temperature from 450 ℃ to the pre-sintering temperature at the speed of 2.5 ℃/min, finally raising the temperature to the sintering temperature of 980 ℃ at the speed of 2 ℃/min, preserving the heat for 4.1h, naturally cooling to room temperature, and discharging; and finishing all the working procedures.

Example 3:

the preparation process of the low-loss NiCuZn soft magnetic ferrite material for NFC comprises the following steps:

the method comprises the following steps: mixing the raw materials, and respectively taking Fe according to mass percentage₂O₃:64.00wt％，ZnO:21.00wt％，

NiO 10.00 wt%, CuO for the rest, Fe₂O₃The total content of ZnO, NiO and CuO is 100 wt%;

step two: and (3) performing primary planetary ball milling, namely loading the ingredients obtained in the step one into a planetary ball mill, loading zirconium balls and distilled water into the planetary ball mill, mixing the zirconium balls and the distilled water according to the mass ratio of grinding balls to materials to distilled water of 1.9: 1: 0.9, and performing ball milling for 5.9 hours at the rotating speed of 400 +/-5 revolutions per minute to obtain the slurry of the main component.

Step three: pre-burning at high temperature, namely pre-burning the powder obtained by drying the main component slurry obtained in the step two in a drying box, heating to 700 ℃ from room temperature at the heating rate of 1.9 ℃/min, preserving heat for 1.9h, cooling to room temperature along with the furnace, and discharging;

step four: doping with trace elements, mixingGrinding and crushing the powder presintered in the third step, and adding V₂O₅And Co₂O₃，V₂O₅Is 0.3 wt% of the main component, Co₂O₃The content of (B) is 0.8 wt% of the main component;

step five: performing secondary planetary ball milling, namely loading the ingredients obtained in the fourth step into a planetary ball mill, mixing the ingredients according to the mass ratio of grinding balls to the ingredients to distilled water of 1.9: 1: 1.1, performing ball milling for 8.1h at the rotating speed of 400 +/-5 revolutions per minute, and drying the milled slurry in a drying oven;

step six: granulating and molding, namely adding a polyvinyl alcohol (PVA) solution into the powder prepared in the fifth step according to 7 wt% of the material weight for granulation, screening the manufactured spherical particles by using 60-mesh and 120-mesh screens, taking the powder between the 60-mesh and 120-mesh screens, and performing cold press molding on the powder into a sample ring blank body by using a 30T full-automatic powder molding machine, wherein the molding pressure is 6 MPa;

step seven: and (3) high-temperature gradient sintering, namely putting the sample blank formed in the step six into a box type electric furnace for high-temperature sintering, wherein the temperature rise gradient is as follows: raising the temperature from room temperature to 430 ℃ at the speed of 2 ℃/min, preserving the heat at 430 ℃ for 2.1h, then raising the temperature from 430 ℃ to the pre-sintering temperature at the speed of 3 ℃/min, finally raising the temperature to the sintering temperature of 960 ℃ at the speed of 25 ℃/min, preserving the heat for 4.1h, naturally cooling to room temperature, and discharging; and finishing all the working procedures.

Example 4:

the preparation process of the low-loss NiCuZn soft magnetic ferrite material for NFC comprises the following steps:

the method comprises the following steps: mixing the raw materials, and respectively taking Fe according to mass percentage₂O₃64.00 wt%, 20.00 wt% ZnO, 11.00 wt% NiO and the balance CuO₂O₃The total content of ZnO, NiO and CuO is 100 wt%;

step two: and (3) performing primary planetary ball milling, namely loading the ingredients obtained in the step one into a planetary ball mill, loading zirconium balls and distilled water into the planetary ball mill, mixing the zirconium balls and the distilled water according to the mass ratio of grinding balls to materials to distilled water of 2 to 1 to 1.1, and performing ball milling for 6 hours at the rotating speed of 400 +/-5 revolutions per minute to obtain the slurry of the main component.

Step three: pre-burning at high temperature, namely pre-burning the powder obtained by drying the main component slurry obtained in the step two in a drying box, raising the temperature to 750 ℃ at the heating rate of 2 ℃/min from room temperature, preserving the temperature for 2.1h, cooling the powder to room temperature along with the furnace, and discharging the powder;

step four: doping trace elements, grinding and crushing the powder subjected to the pre-sintering in the third step, and adding V₂O₅And Co₂O₃，V₂O₅Is 0.3 wt% of the main component, Co₂O₃The content of (B) is 0.7 wt% of the main component;

step five: performing secondary planetary ball milling, namely loading the ingredients obtained in the fourth step into a planetary ball mill, mixing the ingredients according to the mass ratio of grinding balls to the ingredients to distilled water of 2: 1, performing ball milling for 8 hours at a rotating speed of 400 +/-5 revolutions per minute, and drying the milled slurry in a drying oven;

step six: granulating and molding, namely adding a polyvinyl alcohol (PVA) solution into the powder prepared in the fifth step according to 7 wt% of the material weight for granulation, screening the manufactured spherical particles by using 60-mesh and 120-mesh screens, taking the powder between the 60-mesh and 120-mesh screens, and performing cold press molding on the powder into a sample ring blank body by using a 30T full-automatic powder molding machine, wherein the molding pressure is 6 MPa;

step seven: and (3) high-temperature gradient sintering, namely putting the sample blank formed in the step six into a box type electric furnace for high-temperature sintering, wherein the temperature rise gradient is as follows: raising the temperature from room temperature to 450 ℃ at the speed of 1.5 ℃/min, preserving the heat at 450 ℃ for 1.9h, then raising the temperature from 450 ℃ to 900 ℃ at the speed of 2 ℃/min, finally raising the temperature to the sintering temperature of 960 ℃ at the speed of 1.0 ℃/min, preserving the heat for 4h, naturally cooling to room temperature, and discharging; and finishing all the working procedures.

Example 5

The preparation process of the low-loss NiCuZn soft magnetic ferrite material for NFC comprises the following steps:

the method comprises the following steps: mixing the raw materials, and respectively taking Fe according to mass percentage₂O₃63 wt%, ZnO 25 wt%, NiO 7 wt%, and CuO for the rest, Fe₂O₃The total content of ZnO, NiO and CuO is 100 wt%;

step two: and (3) performing primary planetary ball milling, namely loading the ingredients obtained in the step one into a planetary ball mill, and loading zirconium balls and distilled water into the planetary ball mill to perform ball milling for 6 hours at the rotating speed of 400 +/-5 revolutions per minute to obtain the slurry of the main component.

Step three: pre-burning at high temperature, namely pre-burning the powder obtained by drying the main component slurry obtained in the step two in a drying box, raising the temperature to 750 ℃ at the heating rate of 2 ℃/min from room temperature, preserving the temperature for 2h, cooling to room temperature along with the furnace, and discharging;

step four: doping trace elements, grinding and crushing the powder subjected to the pre-sintering in the third step, and adding V₂O₅And Co₂O₃，V₂O₅Is 0.4 wt% of the main component, Co₂O₃The content of (B) is 0.6 wt% of the main component;

step five: performing secondary planetary ball milling, namely loading the ingredients obtained in the fourth step into a planetary ball mill, mixing the ingredients according to the mass ratio of grinding balls to the ingredients to distilled water of 2.1: 1: 1.1, performing ball milling for 8 hours at a rotating speed of 400 +/-5 revolutions per minute, and drying the milled slurry in a drying oven;

step six: granulating and molding, namely adding a polyvinyl alcohol (PVA) solution into the powder prepared in the fifth step according to 7 wt% of the material weight for granulation, screening the manufactured spherical particles by using 60-mesh and 120-mesh screens, taking the powder between the 60-mesh and 120-mesh screens, and performing cold press molding on the powder into a sample ring blank body by using a 30T full-automatic powder molding machine, wherein the molding pressure is 6 MPa;

step seven: and (3) high-temperature gradient sintering, namely putting the sample blank formed in the step six into a box type electric furnace for high-temperature sintering, wherein the temperature rise gradient is as follows: raising the temperature from room temperature to 470 ℃ at the speed of 1.5 ℃/min, preserving the heat at 470 ℃ for 2h, then raising the temperature from 470 ℃ to 900 ℃ at the speed of 2.5 ℃/min, finally raising the temperature to 940 ℃ at the speed of 1.5 ℃/min, preserving the heat for 3.9h, naturally cooling to room temperature, and discharging; and finishing all the working procedures.

The samples obtained in examples 1 to 5 were tested by a Hewlett packard HP 4291B impedance analyzer to obtain real parts and imaginary parts of the magnetic rings at different frequencies (FIG. 1(a) -FIG. 1(e)), and the test data of different magnetic rings at 13.56MHz are summarized in Table 1.

TABLE 1

In summary, the low-loss NiCuZn soft magnetic ferrite material for NFC of the present invention can be obtained by sintering at a temperature of less than 1000 ℃, and has a high magnetic permeability (μ' ═ 60-150) and a very small imaginary part (μ ″ less than 3) and a small specific loss factor at 13.56MHz, so as to meet the use requirement of an NFC antenna. The chemical raw materials used in the invention have low price, do not contain toxic and harmful components, have simple process, save energy and have high efficiency, and are convenient for industrialized popularization. The invention co-dopes the auxiliary component V₂O₅And Co₂O₃The sintering temperature of the product is obviously reduced (lower than 1000 ℃), the electromagnetic performance of the soft magnetic ferrite material is greatly improved, and the requirements of NFC, wireless chargers and the like on the performance indexes of the soft magnetic ferrite are met; meanwhile, the small imaginary parts can be ensured at different real parts of magnetic permeability by regulating the ratio of NiO to ZnO at low sintering temperature; in addition, the lower sintering temperature of the preparation method effectively reduces energy consumption and can further integrate the LTCC magnetic inductance device.

It is to be understood that the practice of the present invention is not limited to the following examples, and that any modifications or variations may be made without departing from the scope of the invention.