Nickel-zinc-copper ferrite material as well as preparation method and application thereof

Abstract

The invention provides a nickel-zinc-copper ferrite material and a preparation method and application thereof, the nickel-zinc-copper ferrite material comprises main components and auxiliary components, the main components comprise 49.3 to 55.78 mol% of Fe2O3, 27.2 to 32.94 mol% of ZnO, 5.58 to 8.27 mol% of NiO, 8 to 12 mol% of CuO and 0.02 to 0.8 mol% of CoO; and the auxiliary components comprise CaCO3, Bi2O3 and V2O5 (vanadium pentoxide). According to the nickel-zinc-copper ferrite material disclosed by the invention, by controlling a main component formula and an auxiliary component formula, the nickel-zinc-copper ferrite material has magnetic conductivity of more than 2000 in a temperature range of-55 to 180 DEG C, and is low in temperature coefficient, high in Curie temperature, high in Bs and excellent in mechanical property, and the application range of the nickel-zinc-copper ferrite material in the field of electronic devices is greatly expanded.

Description

Technical Field

[0001] This disclosure belongs to the field of magnetic materials technology, and relates to a nickel-zinc-copper ferrite material, its preparation method and application. Background Technology

[0002] Nickel-zinc power ferrites can be used to create broadband radio frequency (RF) devices, enabling power transmission and impedance transformation of RF signals over a wide frequency range. However, this requires high permeability in the nickel-zinc ferrite. Nickel-zinc ferrite materials with high saturation magnetic flux density and initial permeability greater than 800 are widely used in automotive electronics, serving as key raw materials for power chokes, DC-DC converter coils, transformer coils, linear coils, and some surface-mount components. Therefore, this material has a huge market potential. For devices to function optimally, especially under diverse climatic conditions, the nickel-zinc ferrite material, as the primary raw material, must not only possess high saturation magnetic induction but also exhibit a low temperature coefficient and high mechanical strength over a wide temperature range.

[0003] In the low-frequency range, NiZn-based ferrite materials do not perform as well as MnZn-based materials. However, above 1 MHz, due to their porosity and high resistivity, they significantly outperform MnZn-based materials, becoming the best-performing soft magnetic materials for high-frequency applications. The resistivity ρ of NiZn-based materials can reach 10⁻⁶. 8 With a low Ω·m, NiZn materials exhibit low high-frequency loss, making them particularly suitable for high-frequency applications from 1 to 300 MHz. Furthermore, NiZn-based materials have a higher Curie temperature than MnZn, a higher Bs (up to 0.5T), and a lower coercivity Hc (down to 10 A / m), making them suitable for various inductors, intermediate frequency transformers, filter coils, and chokes. NiZn high-frequency ferrite materials possess a wide bandwidth and low transmission loss, and are commonly used in high-frequency electromagnetic interference (EMI) suppression and surface-mount devices integrating high-frequency power and EMI suppression, serving as EMI and RF interference suppression cores.

[0004] Currently, high-stability nickel-zinc-copper ferrites are widely used in electronic signal transmission, electromagnetic interference suppression technology, and environmental protection and energy conservation. Especially in electronic device applications, nickel-zinc-copper ferrites often require improved overall performance, such as maintaining stable high permeability over a wide temperature range, typically operating within the range of -40 to 90°C. However, military electronic products and civilian electronic products operating in extreme environments often require even higher temperatures, sometimes reaching -55 to 180°C while maintaining stable high permeability. Currently, nickel-zinc-copper ferrites capable of mass production within this temperature range have not yet been publicly disclosed. Therefore, there is a need to develop nickel-zinc-copper ferrite materials with high Bs, high permeability, high Curie temperature, and low temperature coefficient to achieve wider applicability in the electronic signal field.

[0005] Currently, in the development of Ni-Zn-Cu ferrite technology, the focus in the field of nickel-zinc-copper ferrite materials with wide temperature range, high magnetic permeability, and low temperature coefficient is on effectively controlling parameters such as the range of main component formulations, the types and amounts of additives, molding density, and sintering processes to achieve different properties. For example, CN101863657A discloses a Ni-Zn ferrite with a magnetic permeability of over 2000 in a temperature range of -60℃ to 130℃, with its main components being iron oxide in the range of 51~56 mol% and zinc oxide in the range of 16~26 mol%. However, within its temperature range, the temperature coefficient of magnetic permeability is relatively high, and the Curie temperature is low.

[0006] Based on the above research, there is a need to provide a nickel-zinc-copper ferrite material, which has a low temperature coefficient, high Bs, high Curie temperature and high mechanical strength in the temperature range of -55~180℃. Summary of the Invention

[0007] The purpose of this disclosure is to provide a nickel-zinc-copper ferrite material, its preparation method, and its application. In particular, it designs a nickel-zinc-copper ferrite material with a magnetic permeability of over 2000 in the temperature range of -55 to 180°C, and its preparation method and application. By controlling the formulation of the main component and the auxiliary component, the nickel-zinc-copper ferrite material can achieve a magnetic permeability of over 2000 in the temperature range of -55 to 180°C, with a low temperature coefficient, high Curie temperature, high Bs, and excellent mechanical properties, which greatly increases the application range of Ni-Zn ferrite in the field of electronic devices.

[0008] To achieve this objective, the present disclosure adopts the following technical solution: In a first aspect, this disclosure provides a nickel-zinc-copper ferrite material, which includes a main component and auxiliary components. The main component includes 49.3~55.78 mol% Fe2O3, 27.2~32.94 mol% ZnO, 5.58~8.27 mol% NiO, 8~12 mol% CuO, and 0.02~0.8 mol% CoO. The auxiliary components include CaCO3, Bi2O3 and V2O5.

[0009] This disclosure achieves high magnetic permeability, wide temperature range, low temperature coefficient, and high mechanical strength properties in nickel-zinc-copper ferrite materials by controlling the composition and amount of the main and auxiliary components. Specifically, due to the anisotropy constant K1 > 0 of CoO, and the fact that Co... 2+ The main function of ion addition is to enhance Co 2+The K1 value of ion contribution decreases sharply with increasing temperature, potentially reaching a point below the Curie temperature where K1=0 is the cancellation point. Furthermore, the CoO disclosed herein needs to be added as the main component, making Co... 2+ The ions are more evenly distributed, thus enabling them to function more effectively.

[0010] The main components include 49.3~55.78 mol% Fe2O3, for example, 49.3 mol%, 50 mol%, 50.5 mol%, 51 mol%, 51.5 mol%, 52 mol%, 52.5 mol%, 53 mol%, 53.5 mol%, 54 mol%, 54.5 mol%, 55 mol%, or 55.78 mol%; 27.2~32.94 mol% ZnO, for example, 27.2 mol%, 28 mol%, 28.5 mol%, 29 mol%, 29.5 mol%, 30 mol%, 30.5 mol%, 31 mol%, 31.5 mol%, 32 mol%, 32.5 mol%, or 32.94 mol%; and 5.58~8.27 mol% NiO, for example, 5.58 mol%. The following concentrations are permitted: 6 mol%, 6.5 mol%, 7 mol%, 7.5 mol%, 8 mol%, or 8.27 mol% CuO (e.g., 8 mol%, 9 mol%, 10 mol%, 11 mol%, or 12 mol%); and 0.02 to 0.8 mol% CoO (e.g., 0.02 mol%, 0.05 mol%, 0.1 mol%, 0.15 mol%, 0.2 mol%, 0.25 mol%, 0.3 mol%, 0.35 mol%, 0.4 mol%, 0.45 mol%, 0.5 mol%, 0.55 mol%, 0.6 mol%, 0.65 mol%, 0.7 mol%, 0.75 mol%, or 0.8 mol%), but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] The content of CaCO3 in the auxiliary components, based on the total weight of the main components, is 200~2000ppm, for example, 200ppm, 500ppm, 1000ppm, 1500ppm or 2000ppm; the content of Bi2O3 is 200~2000ppm, for example, 200ppm, 500ppm, 1000ppm, 1500ppm or 2000ppm; the content of V2O5 is 200~2000ppm, for example, 200ppm, 500ppm, 1000ppm, 1500ppm or 2000ppm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] Preferably, the main components include 49.3~51.5 mol% Fe2O3, for example, 49.3 mol%, 50 mol%, 50.5 mol%, 51 mol%, or 51.5 mol%, 28.12~32.6 mol% ZnO, for example, 28.12 mol%, 29 mol%, 29.5 mol%, 30 mol%, 30.5 mol%, 31 mol%, 31.5 mol%, 32 mol%, or 32.6 mol%, and 0.1~0.75 mol%. % CoO, for example, can be 0.1mol%, 0.15mol%, 0.2mol%, 0.25mol%, 0.3mol%, 0.35mol%, 0.4mol%, 0.45mol%, 0.5mol%, 0.55mol%, 0.6mol%, 0.65mol%, 0.7mol%, or 0.75mol%, 6.5~8mol% NiO, for example, can be 6.5mol%, 7mol%, 7.5mol%, or 8mol%, and the balance CuO.

[0013] Preferably, the nickel-zinc-copper ferrite material has a specific temperature coefficient of magnetic permeability of -6.2 to 5 ppm (-6.2 to 5 × 10⁻⁶) within a temperature range of -55 to 200°C. -6 For example, it could be -6.2ppm, -2ppm, 2ppm, 4ppm or 5ppm, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] Preferably, the nickel-zinc-copper ferrite material has a magnetic permeability of 2000~2250 in the temperature range of -55~200℃, for example, it can be 2000, 2050, 2100, 2150, 2200 or 2250, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Preferably, the Curie temperature of the nickel-zinc-copper ferrite material is >200℃, for example, it can be 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃ or 240℃; the Bs is above 440mT, for example, it can be 440mT, 445mT, 450mT, 455mT, 460mT, 465mT, 470mT, 475mT, 480mT or 485mT; and the flexural strength is ≥200MPa, for example, it can be 200MPa, 210MPa, 220MPa, 230MPa, 240MPa, 250MPa, 260MPa, 270MPa or 280MPa, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0016] Secondly, this disclosure provides a method for preparing the nickel-zinc-copper ferrite material as described in the first aspect, the method comprising the following steps: (1) The main components are pre-fired to obtain pre-fired material; (2) Mix the pre-burned material and auxiliary components described in step (1) to obtain a ferrite mixture; (3) Temper the ferrite mixture described in step (2) to obtain tempered material; (4) The tempering material described in step (4) is mixed with the binder and spray granulated to obtain ferrite granules; (5) Press the ferrite particles described in step (4) into a molded body, and then sinter the molded body to obtain the nickel-zinc-copper ferrite material.

[0017] This disclosure is made so that Co 2+ Ions and other auxiliary ions can better exert their properties, taking Co 2+ Using ions as the main component and employing a pre-firing-tempering-low-temperature gradient sintering preparation process, the aim is to make Co... 2+ The more uniform distribution of ions and plasma enables Ni-Zn-Cu ferrite materials to achieve high initial permeability, wide temperature range, low temperature coefficient, and high mechanical strength.

[0018] Preferably, the main component in step (1) is first wet ball milled and dried before the pre-calcination.

[0019] Preferably, the pre-firing temperature in step (1) is 650~800℃, for example, 650℃, 700℃, 750℃ or 800℃, and the time is 2~3h, for example, 2h, 2.5h or 3h, and it is carried out in an air atmosphere.

[0020] Preferably, the method of mixing the pre-burned material and auxiliary components in step (1) in step (2) includes wet sand milling.

[0021] Preferably, the wet sand milling time is 70-100 min, for example, it can be 70 min, 75 min, 80 min, 85 min, 90 min or 100 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the tempering temperature in step (3) is 700~850℃, for example, 700℃, 750℃, 800℃ or 850℃, and the time is 1~3h, for example, 1h, 1.5h, 2h, 2.5h or 3h, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, the binder in step (4) is 1 to 2 wt% of the tempering material, for example, it can be 1 wt%, 1.5 wt% or 2 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, the adhesive in step (4) comprises PVA (polyvinyl alcohol).

[0025] Preferably, the sintering temperature in step (5) is 950~1200℃, for example, 950℃, 1000℃, 1050℃, 1100℃, 1150℃ or 1200℃, and the time is 4~10h, for example, 4h, 6h, 8h or 10h, and it is carried out in an air atmosphere.

[0026] Preferably, the sintering in step (5) is a three-stage gradient sintering, which includes first sintering at 500~700℃, for example, 500℃, 600℃ or 700℃ for 1~3h, for example, 1h, 2h or 3h; then raising the temperature to 750~900℃, for example, 750℃, 800℃, 850℃ or 900℃, for 4~8h, for example, 4h, 5h, 6h, 7h or 8h; and finally raising the temperature to 1000~1200℃, for example, 1000℃, 1100℃ or 1200℃, for 5~7h, for example, 5h, 6h or 7h, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] The heating rate to 1000~1200℃ is 3~6℃ / min, for example, it can be 3℃ / min, 4℃ / min, 5℃ / min or 6℃ / min. The time to heat up to 750~900℃ is 6~10h, for example, it can be 6h, 7h, 8h, 9h or 10h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Thirdly, this disclosure provides an application of the nickel-zinc-copper ferrite material as described in the first aspect, including its use in the field of electronic devices.

[0029] Compared with the prior art, this disclosure has the following beneficial effects: This disclosure achieves high magnetic permeability, wide temperature range, low temperature coefficient, and high mechanical strength properties in nickel-zinc-copper ferrite materials by controlling the composition and amount of the main and auxiliary components. Specifically, due to the anisotropy constant K1 > 0 of CoO, and the fact that Co... 2+ The main function of ion addition is to enhance Co 2+The K1 value of ion contribution decreases sharply with increasing temperature, potentially reaching a point below the Curie temperature where K1=0 is the cancellation point. Furthermore, the CoO disclosed herein needs to be added as the main component, making Co... 2+ The ions are more evenly distributed, thus enabling them to function more effectively. Attached Figure Description

[0030] Figure 1 This is a SEM image of the nickel-zinc-copper ferrite material described in Embodiment 1 of this disclosure. Detailed Implementation

[0031] The technical solutions of this disclosure will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of this disclosure and should not be construed as specific limitations thereof.

[0032] Example 1 This embodiment provides a nickel-zinc-copper ferrite material, which includes a main component and auxiliary components. The main component includes 50.78 mol% Fe2O3, 31.64 mol% ZnO, 7.36 mol% NiO, 10 mol% CuO, and 0.22 mol% CoO. Based on the total weight of the main component, the auxiliary components contain 200 ppm CaCO3, 2000 ppm Bi2O3, and 200 ppm V2O5. The preparation method of the nickel-zinc-copper ferrite material includes the following steps: (1) After accurately weighing the five main components of the designed formula, which are Fe2O3: 50.78mol%, NiO: 7.36mol%, ZnO: 31.64mol%, CuO: 10mol%, and CoO: 0.22mol%, put them into a ball mill for ball milling until uniform, put them into an oven for drying, and then pre-calcined at 750℃ for 2.5 hours to obtain pre-calcined powder. (2) Next, add the auxiliary components of the formula to the pre-calcined powder. The auxiliary components are calculated based on the total amount of the main components, namely CaCO3: 200ppm, Bi2O3: 2000ppm, and V2O5: 200ppm. The powder is ball-milled in a sand mill for 70 minutes, then dried, and then tempered at 750℃ for 2 hours to obtain the tempered material. (3) The tempering material described in step (2) is mixed with 1 wt% PVA, and then ferrite granules are obtained by spray granulation and sieved.

[0033] (4) The ferrite particles described in step (3) are pressed into blanks with dimensions of H25×15×8 using a press, and then sintered in air at 600℃ for 3 hours. The temperature is then increased to 900℃ and sintered for 6 hours. The temperature is further increased to 1200℃ at a rate of 6℃ / min and sintered for 6 hours. Then, the temperature is rapidly reduced to 600℃ in air at a rate of 7℃ / min, and then further reduced to 50℃ at a rate of 2℃ / min to obtain the magnetic core. The grain morphology of the nickel-zinc-copper ferrite material in the magnetic core is shown in the figure below. Figure 1 As shown.

[0034] Example 2 This embodiment provides a nickel-zinc-copper ferrite material, which includes a main component and auxiliary components. The main component includes 49.56 mol% Fe2O3, 32.25 mol% ZnO, 6.58 mol% NiO, 11 mol% CuO, and 0.61 mol% CoO. Based on the total weight of the main component, the auxiliary components contain 400 ppm CaCO3, 1600 ppm Bi2O3, and 500 ppm V2O5. The preparation method of the nickel-zinc-copper ferrite material includes the following steps: (1) After accurately weighing the five main components of the designed formula, Fe2O3: 49.56mol%, NiO: 6.58mol%, ZnO: 32.25mol%, CuO: 11mol%, CoO: 0.61mol%, put them into a ball mill for ball milling and mixing until uniform. After drying in an oven, pre-calcining at 700℃ for 3 hours to obtain pre-calcined powder. (2) Next, add the auxiliary components of the formula to the pre-calcined powder. The auxiliary components are calculated based on the total amount of the main components, namely CaCO3: 400ppm, Bi2O3: 1600ppm, and V2O5: 500ppm. The powder is ball-milled in a sand mill for 80 minutes, then dried, and then tempered at 800℃ for 2.5 hours to obtain tempered material. (3) The tempering material described in step (2) is mixed with 2wt% PVA, and then ferrite granules are obtained by spray granulation and sieved.

[0035] (4) The ferrite granules described in step (3) are pressed into blanks with dimensions of H25×15×8 by a press, and then sintered in air at 650°C for 2.5 hours. Then, the temperature is raised to 880°C and sintered for 5 hours. The temperature is then raised to 1100°C at a rate of 3.5°C / min and sintered for 7 hours. Finally, the temperature is lowered in air with the furnace to obtain the magnetic core for testing.

[0036] Example 3 This embodiment provides a nickel-zinc-copper ferrite material, which includes a main component and auxiliary components. The main component includes 51.5 mol% Fe2O3, 32.5 mol% ZnO, 6.94 mol% NiO, 9 mol% CuO, and 0.06 mol% CoO. Based on the total weight of the main component, the auxiliary components contain 200 ppm CaCO3, 800 ppm Bi2O3, and 200 ppm V2O5. The preparation method of the nickel-zinc-copper ferrite material includes the following steps: (1) After accurately weighing the five main components of the designed formula, which are Fe2O3: 51.5mol%, NiO: 6.94mol%, ZnO: 32.5mol%, CuO: 9mol%, and CoO: 0.06mol%, put them into a ball mill for ball milling until uniform, put them into an oven for drying, and then pre-calcined at 800℃ for 2 hours to obtain pre-calcined powder. (2) Next, add the auxiliary components of the formula to the pre-calcined powder. The auxiliary components are calculated based on the total amount of the main components, namely CaCO3: 200ppm, Bi2O3: 800ppm, and V2O5: 200ppm. The powder is ball-milled in a sand mill for 100 minutes, then dried, and then tempered at 850℃ for 2 hours to obtain the tempered material. (3) The tempering material described in step (2) is mixed with 1.5 wt% PVA, and then ferrite granules are obtained by spray granulation and sieved.

[0037] (4) The ferrite granules described in step (3) are pressed into blanks with dimensions of H25×15×8 by a press, and then sintered in air at 700℃ for 2 hours. Then, the temperature is raised to 860℃ and sintered for 8 hours. The temperature is then raised to 1000℃ at a rate of 4℃ / min and sintered for 7 hours. Finally, the temperature is lowered in air to obtain the magnetic core for testing.

[0038] Example 4 This embodiment provides a nickel-zinc-copper ferrite material, which is the same as in Example 1 except that the main components include 54.42 mol% Fe2O3, 27.2 mol% ZnO, 5.58 mol% NiO, 12 mol% CuO and 0.8 mol% CoO.

[0039] The preparation method of the nickel-zinc-copper ferrite material is the same as that in Example 1, except that the formulation amount is adapted to change.

[0040] Example 5 This embodiment provides a nickel-zinc-copper ferrite material, which is the same as in Example 1 except that the main components include 51.28 mol% Fe2O3, 32.5 mol% ZnO, 8.2 mol% NiO, 8 mol% CuO and 0.02 mol% CoO.

[0041] The preparation method of the nickel-zinc-copper ferrite material is the same as that in Example 1, except that the formulation amount is adapted to change.

[0042] Example 6 This embodiment provides a nickel-zinc-copper ferrite material. Except for the fact that the tempering process in step (2) is not performed in the preparation method, so that the adaptability of the obtained nickel-zinc-copper ferrite material is changed, the rest of the nickel-zinc-copper ferrite material is the same as that in embodiment 1.

[0043] Example 7 This embodiment provides a nickel-zinc-copper ferrite material. Except for the preparation method, in step (4), the blank is placed in air and sintered at 700°C for 2 hours, and then heated to 1000°C at a heating rate of 4°C / min and sintered for 7 hours to change the adaptability of the obtained nickel-zinc-copper ferrite material, the rest is the same as in embodiment 1.

[0044] Example 8 This embodiment provides a nickel-zinc-copper ferrite material, which includes a main component and auxiliary components. The main component includes 49.3 mol% Fe2O3, 32.94 mol% ZnO, 8.27 mol% NiO, 8.74 mol% CuO, and 0.75 mol% CoO. Based on the total weight of the main component, the auxiliary components contain 2000 ppm CaCO3, 200 ppm Bi2O3, and 2000 ppm V2O5. The preparation method of the nickel-zinc-copper ferrite material includes the following steps: (1) After accurately weighing the five main components of the designed formula, Fe2O3:49.3mol%, NiO:8.27mol%, ZnO:32.94mol%, CuO:8.74mol%, CoO:0.75mol%, they were put into a ball mill for ball milling and mixed until uniform. After drying in an oven, they were pre-calcined at 650℃ for 3 hours to obtain pre-calcined powder. (2) Next, add the auxiliary components of the formula to the pre-calcined powder. The auxiliary components are calculated based on the total amount of the main components, namely CaCO3: 2000ppm, Bi2O3: 200ppm, and V2O5: 2000ppm. The powder is ball-milled in a sand mill for 70 minutes, then dried, and then tempered at 700℃ for 3 hours to obtain the tempered material. (3) The tempering material described in step (2) is mixed with 1 wt% PVA, and then ferrite granules are obtained by spray granulation and sieved.

[0045] (4) The ferrite granules described in step (3) are pressed into blanks with dimensions of H25×15×8 by a press, and then sintered in air at 500°C for 3 hours. Then, the temperature is raised to 750°C and sintered for 8 hours. The temperature is then raised to 1000°C at a rate of 6°C / min and sintered for 5 hours. Then, the temperature is rapidly cooled to 600°C in air at a rate of 7°C / min, and then cooled to 50°C at a rate of 2°C / min. The magnetic core can then be obtained for testing.

[0046] Example 9 This embodiment provides a nickel-zinc-copper ferrite material, which includes a main component and auxiliary components. The main component includes 55.78 mol% Fe2O3, 28.12 mol% ZnO, 8 mol% NiO, 8 mol% CuO, and 0.1 mol% CoO. Based on the total weight of the main component, the auxiliary components contain 200 ppm CaCO3, 2000 ppm Bi2O3, and 200 ppm V2O5. The preparation method of the nickel-zinc-copper ferrite material includes the following steps: (1) After accurately weighing the five main components of the designed formula, Fe2O3: 55.78 mol%, NiO: 8 mol%, ZnO: 28.12 mol%, CuO: 8 mol%, CoO: 0.1 mol%, put them into a ball mill for ball milling and mixing until uniform. After drying in an oven, pre-calcining at 750℃ for 2 hours to obtain pre-calcined powder. (2) Next, add the auxiliary components of the formula to the pre-calcined powder. The auxiliary components are calculated based on the total amount of the main components, namely CaCO3: 200ppm, Bi2O3: 2000ppm, and V2O5: 200ppm. The powder is ball-milled in a sand mill for 70 minutes, then dried, and then tempered at 850℃ for 1 hour to obtain the tempered material. (3) The tempering material described in step (2) is mixed with 1 wt% PVA, and then ferrite granules are obtained by spray granulation and sieved.

[0047] (4) The ferrite granules described in step (3) are pressed into blanks with dimensions of H25×15×8 by a press, and then sintered in air at 700°C for 1 hour. Then, the temperature is raised to 900°C and sintered for 4 hours. The temperature is then raised to 1200°C at a rate of 6°C / min and sintered for 5 hours. Then, the temperature is rapidly cooled to 600°C in air at a rate of 7°C / min, and then cooled to 50°C at a rate of 2°C / min. The magnetic core can then be obtained for testing.

[0048] Comparative Example 1 This comparative example provides a nickel-zinc-copper ferrite material, which includes a main component and auxiliary components. The main component includes 49.7 mol% Fe2O3, 32.4 mol% ZnO, 7.3 mol% NiO, and 10.6 mol% CuO. Based on the total weight of the main component, the auxiliary components contain 400 ppm CaCO3, 400 ppm Bi2O3, 2000 ppm CoO, and 200 ppm V2O5. The preparation method of the nickel-zinc-copper ferrite material includes the following steps: (1) After accurately weighing the four main components of the design formula, Fe2O3:49.7mol%, NiO:7.3mol%, CuO:10.6mol%, ZnO:32.4mol%, put them into a ball mill for ball milling and mixing until uniform. After drying in an oven, pre-calcining at 750℃ for 2 hours to obtain pre-calcined powder. (2) Next, add the auxiliary components of the formula to the pre-calcined powder. The auxiliary components are calculated based on the total amount of the main components: CaCO3: 400ppm, Bi2O3: 400ppm, CoO: 2000ppm, V2O5: 200ppm. The powder is ball-milled in a sand mill for 80 minutes, then dried, mixed with 1.5wt% PVA, and then granulated by spraying to obtain ferrite particles, which are then sieved.

[0049] (3) The ferrite particles described in step (2) are pressed into blanks with dimensions of H25×15×8 by a press, and then sintered in air at 680°C for 7 hours. Then, the temperature is increased to 1200°C at a heating rate of 4°C / min and sintered for 1.5 hours. The cooling stage is carried out in air with balanced oxygen partial pressure. The magnetic core can then be obtained for testing.

[0050] Comparative Example 2 This comparative example provides a nickel-zinc-copper ferrite material, which includes a main component and auxiliary components. The main component includes 53.0 mol% Fe2O3, 29.6 mol% ZnO, 8 mol% NiO, 8.8 mol% CuO, and 0.6 mol% CoO. Based on the total weight of the main component, the auxiliary components contain 400 ppm CaCO3, 400 ppm Bi2O3, 1000 ppm CoO, and 200 ppm V2O5. The preparation method of the nickel-zinc-copper ferrite material includes the following steps: (1) After accurately weighing the five main components with the design formula of Fe2O3: 53.0 mol%, NiO: 8 mol%, CuO: 8.8 mol%, ZnO: 29.6 mol%, and CoO: 0.6 mol%, put them into a ball mill for ball milling and mixing until uniform. After drying in an oven, pre-calcining at 750℃ for 2 hours to obtain pre-calcined powder. (2) Next, add the auxiliary components of the formula to the pre-calcined powder. The auxiliary components are calculated based on the total amount of the main components: CaCO3: 400ppm, Bi2O3: 400ppm, CoO: 1000ppm, V2O5: 200ppm. The powder is ball-milled in a sand mill for 70 minutes, then dried, mixed with 1.5wt% PVA, and then granulated by spraying to obtain ferrite particles, which are then sieved.

[0051] (3) The ferrite particles described in step (2) are pressed into blanks with dimensions of H25×15×8 by a press, and then sintered in air at 900℃ for 7 hours. Then, the temperature is increased to 1130℃ at a heating rate of 5℃ / min and sintered for 1.5 hours. The cooling stage is carried out in air with balanced oxygen partial pressure. The magnetic core can then be obtained for testing.

[0052] Comparative Example 3 This comparative example provides a nickel-zinc-copper ferrite material, which includes a main component and auxiliary components. The main component includes 53.9 mol% Fe2O3, 29.7 mol% ZnO, 7.0 mol% NiO, and 9.4 mol% CuO. Based on the total weight of the main component, the auxiliary components contain 400 ppm CaCO3, 1400 ppm Bi2O3, and 200 ppm V2O5. The preparation method of the nickel-zinc-copper ferrite material includes the following steps: (1) After accurately weighing the four main components with the designed formula of Fe2O3: 53.9mol%, NiO: 7.0mol%, ZnO: 29.7mol%, CuO: 9.4mol%, put them into a ball mill for ball milling and mixing until uniform. After drying in an oven, pre-calcining at 750℃ for 2 hours to obtain pre-calcined powder. (2) Next, add the auxiliary components of the formula to the pre-calcined powder. The auxiliary components are calculated based on the total amount of the main components, namely CaCO3: 400ppm, Bi2O3: 1400ppm, and V2O5: 200ppm. The powder is ball-milled in a sand mill for 100 minutes, then dried, mixed with 1.5wt% PVA, and then granulated by spraying to obtain ferrite particles and sieved.

[0053] (3) The ferrite granules described in step (2) are pressed into blanks with dimensions of H25×15×8 by a press, and then sintered in air at 1110℃ for 7 hours. The cooling stage is carried out under balanced oxygen partial pressure air, and then the furnace is cooled down to obtain the magnetic core for testing.

[0054] The magnetic cores obtained in the above embodiments and comparative examples were tested for initial permeability, specific temperature coefficient, saturation magnetic flux density, Curie temperature, and mechanical strength. The test conditions are shown in Table 1. Table 1 Among them, the mechanical strength was calculated by testing the three-point bending strength of the dry-pressed sintered product strip T65×6×4mm.

[0055] The test results of the initial permeability of the magnetic cores obtained from the above embodiments and comparative examples are shown in Table 2: Table 2 The specific temperature coefficient α of the magnetic cores obtained in the above embodiments and comparative examples μr / μi The test results are shown in Table 3: Table 3 The saturation magnetic flux density Bs, Curie temperature Tc, and mechanical strength P of the magnetic cores obtained in the above embodiments and comparative examples are shown in Table 4: Table 4 As can be seen from Table 2-4: As can be seen from Examples 1-3, Examples 8-9, and Comparative Examples 1-3, this disclosure, by controlling the composition and amount of the main and auxiliary components, and simultaneously controlling the preparation method of the nickel-zinc-copper ferrite material, enables the nickel-zinc-copper ferrite material to possess properties such as high magnetic permeability, wide temperature range, low temperature coefficient, and high mechanical strength. In contrast, the magnetic permeability of Comparative Examples 1-3 has a relatively high temperature coefficient in the range of -55 to 180°C, and the magnetic permeability changes significantly with temperature, which cannot guarantee the normal operation of electronic devices within this temperature range. As can be seen from Examples 1 and 4-5, this disclosure, by further optimizing the content of the main components, can further improve the performance of the nickel-zinc-copper ferrite material. As can be seen from Examples 1 and 6-7, when tempering is not performed, or if only two-stage gradient sintering is performed, ion dispersion will be affected, thereby affecting the performance of the nickel-zinc-copper ferrite material.

[0056] The above description is only a specific embodiment of this disclosure, but the protection scope of this disclosure is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this disclosure fall within the protection and disclosure scope of this disclosure.

Claims

1. A nickel-zinc-copper ferrite material, characterized in that, The nickel-zinc-copper ferrite material comprises a main component and auxiliary components. The main component comprises 49.3~55.78 mol% Fe2O3, 27.2~32.94 mol% ZnO, 5.58~8.27 mol% NiO, 8~12 mol% CuO, and 0.02~0.8 mol% CoO. The auxiliary components include CaCO3, Bi2O3 and V2O5.

2. The nickel-zinc-copper ferrite material according to claim 1, characterized in that, Based on the total weight of the main components, the auxiliary components contain 200~2000ppm of CaCO3, 200~2000ppm of Bi2O3, and 200~2000ppm of V2O5. Preferably, the main components include 49.3~51.5 mol% Fe2O3, 28.12~32.6 mol% ZnO, 0.1~0.75 mol% CoO, 6.5~8 mol% NiO, and the balance CuO.

3. The nickel-zinc-copper ferrite material according to claim 1 or 2, characterized in that, The specific temperature coefficient of the magnetic permeability of the nickel-zinc-copper ferrite material is -6.2 to 5 ppm in the temperature range of -55 to 200℃. Preferably, the nickel-zinc-copper ferrite material has a magnetic permeability of 2000~2250 in the temperature range of -55~200℃; Preferably, the nickel-zinc-copper ferrite material has a Curie temperature > 200°C, a Bs value above 440mT, and a flexural strength ≥ 200MPa.

4. A method for preparing a nickel-zinc-copper ferrite material as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) The main components are pre-fired to obtain pre-fired material; (2) Mix the pre-burned material and auxiliary components described in step (1) to obtain a ferrite mixture; (3) Temper the ferrite mixture described in step (2) to obtain tempered material; (4) The tempering material described in step (4) is mixed with the binder and spray granulated to obtain ferrite granules; (5) Press the ferrite particles described in step (4) into a molded body, and then sinter the molded body to obtain the nickel-zinc-copper ferrite material.

5. The preparation method according to claim 4, characterized in that, The main component described in step (1) is first wet ball milled and dried, and then pre-calcined; Preferably, the pre-firing temperature in step (1) is 650~800℃, the time is 2~3h, and it is carried out in an air atmosphere.

6. The preparation method according to claim 4 or 5, characterized in that, The mixing method for the pre-fired material and auxiliary components in step (1) in step (2) includes wet sand milling; Preferably, the wet sand milling time is 70-100 minutes.

7. The preparation method according to any one of claims 4-6, characterized in that, The tempering temperature in step (3) is 700~850℃, and the time is 1~3h; Preferably, the binder in step (4) is 1 to 2 wt% of the tempering material.

8. The preparation method according to any one of claims 4-7, characterized in that, The sintering temperature in step (5) is 950~1200℃, the time is 4~10h, and it is carried out in an air atmosphere.

9. The preparation method according to claim 8, characterized in that, The sintering in step (5) is a three-stage gradient sintering, which includes sintering at 500~700℃ for 1~3h, then heating to 750~900℃ for 4~8h, and finally heating to 1000~1200℃ for 5~7h.

10. An application of the nickel-zinc-copper ferrite material as described in any one of claims 1-3, characterized in that, The applications include those in the field of electronic devices.

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