Intermediate-frequency low-temperature-coefficient nickel-copper-zinc ferrite material and preparation method thereof

Abstract

The invention discloses a medium-frequency low-temperature-coefficient nickel-copper-zinc ferrite material and a preparation method thereof, and belongs to the technical field of ferrite material preparation. The material comprises a main material and an additive, the main material is prepared from the following raw materials in percentage by mole: 40.5%-42.5% of Fe2O3, 29.5%-31.5% of NiO2, 5.6%-6% of CuO and the balance of ZnO by taking the total molar weight of the main material as 100%; the additive comprises the following components in percentage by weight: 0.15 to 0.3 percent of Co2O3, 0.03 to 0.05 percent of CaO and 0.05 to 0.1 percent of SiO2 on the basis that the total weight of the main materials is 100 percent. The intermediate-frequency low-temperature-coefficient nickel-copper-zinc ferrite material has the magnetic conductivity of about 120, the temperature characteristic is stable during working, the electrical property meets the wide-temperature stable use requirement from-40 DEG C to 150 DEG C, and the intermediate-frequency low-temperature-coefficient nickel-copper-zinc ferrite material has wide application prospects in the fields of communication and filtering.

Description

Technical Field

[0001] This invention belongs to the field of ferrite material preparation technology, and relates to a medium-frequency low temperature coefficient nickel-copper-zinc ferrite material and its preparation method. Background Technology

[0002] In the current electronic equipment manufacturing industry, with the rapid development of 5G communication, the Internet of Things, and new energy vehicles, unprecedentedly stringent requirements have been placed on the performance and stability of electronic devices. Inductors, as key components in electronic circuits, directly affect the operation of the entire circuit system. However, with increasing frequency, the permeability of traditional ferrite materials decreases sharply, leading to unstable inductance values. This hinders the effective conversion and storage of electromagnetic energy, affecting the normal operation of the circuit and making it difficult to meet the demands of these emerging fields. Simultaneously, as temperature rises, the inductance of the magnetic core increases, significantly increasing losses. This not only reduces circuit efficiency but may also cause overheating, affecting the reliability and lifespan of the equipment.

[0003] Existing technologies focus on mid-to-high frequency losses and wide temperature performance of 20℃-60℃. However, with the rapid development of 5G communication, the Internet of Things and new energy vehicles, there is a need for higher wide temperature stability, such as stability of -40-150℃.

[0004] Therefore, how to develop a medium-frequency low-temperature coefficient nickel-copper-zinc ferrite material and its preparation method is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a medium-frequency low temperature coefficient nickel-copper-zinc ferrite material and its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A medium-frequency low-temperature-coefficient nickel-copper-zinc ferrite material, comprising main material and additives;

[0008] Based on the total molar amount of the main material being 100%, the main material comprises the following molar percentages of raw materials: Fe2O3 40.5%-42.5%, NiO 29.5%-31.5%, CuO 5.6%-6%, with the balance being ZnO;

[0009] Based on the total weight of the main material as 100%, the additives are 0.15-0.3 wt% Co2O3, 0.03-0.05 wt% CaO, and 0.05-0.1 wt% SiO2.

[0010] This invention also provides a method for preparing a medium-frequency, low-temperature-coefficient nickel-copper-zinc ferrite material, comprising the following steps:

[0011] (1) Weigh each raw material according to the medium-frequency low-temperature coefficient nickel-copper-zinc ferrite material;

[0012] (2) First, mix the main materials, then add water to form a slurry, grind it, and finally add a polyvinyl alcohol solution, spray dry and granulate to obtain granules;

[0013] (3) The granules obtained in step (2) are pre-fired and cooled to obtain pre-fired material;

[0014] (4) Add additives to the pre-burned material obtained in step (3), and grind it to obtain abrasive material;

[0015] (5) Add polyvinyl alcohol solution to the abrasive obtained in step (4), spray dry and granulate to obtain granules, press the granules and sinter them to obtain the medium frequency low temperature coefficient nickel copper zinc ferrite material.

[0016] Furthermore, in step (2), the solid content of the slurry is 50%-65%; the sand milling time is 15-60 min; the mass concentration of the polyvinyl alcohol solution is 8%-10%, and the amount added is 0.5%-1% of the slurry mass.

[0017] Furthermore, in step (3), the pre-firing atmosphere is air, the pre-firing temperature is 800-1050℃, and the pre-firing time is 30-60 min.

[0018] Furthermore, in step (4), the grinding time is 60-150 min, and the grinding is carried out until the average particle size of the abrasive is 0.6-1.5 μm.

[0019] Further, in step (5), the mass concentration of the polyvinyl alcohol solution is 8%-10%, and the amount added is 0.8%-2.5% of the mass of the abrasive; the pressing pressure is 6-10 t / cm. 2 The pressing time is 1-5 seconds, and the material is pressed until the density is 2.8-3.6 g / cm³. 3 The sintering atmosphere is air, the sintering temperature is 1020-1100℃, the heating rate is 2-10℃ / min, and the holding time is 2-6h.

[0020] The present invention has the following beneficial effects: the products prepared by the medium-frequency low temperature coefficient nickel-copper-zinc ferrite material of the present invention are mainly used in the frequency range of 3MHz-5MHz, the inductance change is less than 5%, the application temperature is from -40℃ to 150℃, the inductance change is about 13.7%, which can greatly maintain the stability of the transmitted signal.

[0021] The medium-frequency low temperature coefficient nickel-copper-zinc ferrite material of this invention has a permeability of around 120. It exhibits stable temperature characteristics during operation and meets the requirements for stable use over a wide temperature range of -40℃ to 150℃. It has broad application prospects in the fields of communication and filtering.

[0022] This invention adjusts the Fe2O3 content in the material to a low molar ratio, resulting in an iron-deficient state that allows it to reach an oxidized state during sintering. This leads to a more complete ferrite reaction, achieving a density of 5.3 g / cm³. 3 This method significantly reduces the porosity of the material, adjusts its crystal structure, and further influences its temperature-dependent properties. The frequency of material use is adjusted by increasing the NiO content, primarily by maximizing NiO content to reduce grain growth rate and refine grain size. Simultaneously, Ni... 2+ Partially replaces Fe 3+ By altering the ion distribution in the crystal lattice, the superexchange interaction of AB is enhanced, thereby increasing the cutoff frequency. By adding a proportionally mixed dopant of SiO2 and CaO, grain growth is suppressed and the grains are refined through the formation of grain boundary materials, thus increasing the cutoff frequency. Simultaneously, doping stabilizes the lattice thermal expansion coefficient and reduces the permeability-to-temperature coefficient. Adding Co2O3, which occupies octahedral sites, introduces single-ion anisotropy (K1 > 0), significantly enhancing the anisotropic field of the material, directly increasing the natural resonant frequency, raising the cutoff frequency, and improving the stability of the inductance in the 3-5 MHz range. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] A method for preparing medium-frequency low-temperature-coefficient nickel-copper-zinc ferrite materials includes the following steps:

[0026] (1) Weigh each raw material according to the following requirements:

[0027] Based on the total molar amount of the main ingredients as 100%, the main ingredients include the following raw materials in molar percentages: Fe2O3 41%, NiO 29.8%, CuO 5.8%, ZnO 23.4%;

[0028] Based on the total weight of the main ingredients as 100%, the additives are 0.25wt% Co2O3, 0.05wt% CaO, and 0.1wt% SiO2;

[0029] (2) First, mix the main materials, then add water to form a slurry. The solid content of the slurry is 60%. Sand mill for 45 minutes until the average particle size of the slurry is 0.8 μm. Finally, add polyvinyl alcohol solution with a mass concentration of 9% and an addition amount of 0.8% of the slurry mass. Spray dry and granulate to obtain granules. The process parameters for spray drying and granulation are: inlet temperature 350℃, outlet temperature 115℃, atomizing disc speed 7000 rpm / min, and particle size of granules 60-200 mesh with a content greater than 90%.

[0030] (3) Place the granules obtained in step (2) into a rotary kiln for pre-firing. The pre-firing atmosphere is air, the pre-firing temperature is 950℃, the pre-firing time is 45 min, and the material is cooled to 80℃ to obtain the pre-fired material.

[0031] (4) Add additives to the pre-burned material obtained in step (3), and sand mill for 120 min until the average particle size of the sand mill is 0.9 μm to obtain the sand mill.

[0032] (5) Add polyvinyl alcohol solution to the abrasive obtained in step (4). The mass concentration of the polyvinyl alcohol solution is 9%, and the amount added is 1.8% of the mass of the abrasive. Spray dry granulation is performed. The process parameters for spray drying granulation are: inlet temperature 350℃, outlet temperature 115℃, and atomizing disc speed 7000 rpm / min. Granules are obtained and passed through 80-mesh and 250-mesh sieves. The proportion of 120-200 mesh granules exceeds 75%. The granules are then pressed at a pressure of 8t / cm. 2 The pressing time is 3 seconds, and the density is pressed to 3.2 g / cm³. 3 The material is placed in a muffle furnace for sintering. The sintering atmosphere is air, the sintering temperature is 1080℃, the heating rate is 3℃ / min, and the holding time is 3h, thus obtaining a medium-frequency low temperature coefficient nickel-copper-zinc ferrite material.

[0033] Example 2

[0034] A method for preparing medium-frequency low-temperature-coefficient nickel-copper-zinc ferrite materials includes the following steps:

[0035] (1) Weigh each raw material according to the following requirements:

[0036] Based on the total molar amount of the main material being 100%, the main material includes the following raw materials in molar percentages: Fe2O3 41.5%, NiO 29.5%, CuO 6%, ZnO 23%;

[0037] Based on the total weight of the main ingredients as 100%, the additives are 0.2 wt% Co2O3, 0.03 wt% CaO, and 0.1 wt% SiO2;

[0038] (2) First, mix the main materials, then add water to form a slurry. The solid content of the slurry is 60%. Sand mill for 45 minutes until the average particle size of the slurry is 0.8 μm. Finally, add polyvinyl alcohol solution with a mass concentration of 9% and an addition amount of 0.8% of the slurry mass. Spray dry and granulate to obtain granules. The process parameters for spray drying and granulation are: inlet temperature 350℃, outlet temperature 115℃, atomizing disc speed 7000 rpm / min, and particle size of granules 60-200 mesh with a content greater than 90%.

[0039] (3) Place the granules obtained in step (2) into a rotary kiln for pre-firing. The pre-firing atmosphere is air, the pre-firing temperature is 950℃, the pre-firing time is 45 min, and the material is cooled to 80℃ to obtain the pre-fired material.

[0040] (4) Add additives to the pre-burned material obtained in step (3), and sand mill for 120 min until the average particle size of the sand mill is 0.9 μm to obtain the sand mill.

[0041] (5) Add polyvinyl alcohol solution to the abrasive obtained in step (4). The mass concentration of the polyvinyl alcohol solution is 9%, and the amount added is 1.8% of the mass of the abrasive. Spray dry granulation is performed. The process parameters for spray drying granulation are: inlet temperature 350℃, outlet temperature 115℃, and atomizing disc speed 7000 rpm / min. Granules are obtained and passed through 80-mesh and 250-mesh sieves. The proportion of 120-200 mesh granules exceeds 75%. The granules are then pressed at a pressure of 8t / cm. 2 The pressing time is 3 seconds, and the density is pressed to 3.2 g / cm³. 3 The material is placed in a muffle furnace for sintering. The sintering atmosphere is air, the sintering temperature is 1080℃, the heating rate is 3℃ / min, and the holding time is 3h, thus obtaining a medium-frequency low temperature coefficient nickel-copper-zinc ferrite material.

[0042] Example 3

[0043] A method for preparing medium-frequency low-temperature-coefficient nickel-copper-zinc ferrite materials includes the following steps:

[0044] (1) Weigh each raw material according to the following requirements:

[0045] Based on the total molar amount of the main ingredients as 100%, the main ingredients include the following raw materials in molar percentages: Fe2O3 41.5%, NiO 31%, CuO 5.6%, ZnO 21.9%;

[0046] Based on the total weight of the main ingredients as 100%, the additives are 0.15wt% Co2O3, 0.03wt% CaO, and 0.08wt% SiO2;

[0047] (2) First, mix the main materials, then add water to form a slurry. The solid content of the slurry is 60%. Sand mill for 45 minutes until the average particle size of the slurry is 0.8 μm. Finally, add polyvinyl alcohol solution with a mass concentration of 9% and an addition amount of 0.8% of the slurry mass. Spray dry and granulate to obtain granules. The process parameters for spray drying and granulation are: inlet temperature 350℃, outlet temperature 115℃, atomizing disc speed 7000 rpm / min, and particle size of granules 60-200 mesh with a content greater than 90%.

[0048] (3) Place the granules obtained in step (2) into a rotary kiln for pre-firing. The pre-firing atmosphere is air, the pre-firing temperature is 950℃, the pre-firing time is 45 min, and the material is cooled to 80℃ to obtain the pre-fired material.

[0049] (4) Add additives to the pre-burned material obtained in step (3), and sand mill for 120 min until the average particle size of the sand mill is 0.9 μm to obtain the sand mill.

[0050] (5) Add polyvinyl alcohol solution to the abrasive obtained in step (4). The mass concentration of the polyvinyl alcohol solution is 9%, and the amount added is 1.8% of the mass of the abrasive. Spray dry granulation is performed. The process parameters for spray drying granulation are: inlet temperature 350℃, outlet temperature 115℃, and atomizing disc speed 7000 rpm / min. Granules are obtained and passed through 80-mesh and 250-mesh sieves. The proportion of 120-200 mesh granules exceeds 75%. The granules are then pressed at a pressure of 8t / cm. 2 The pressing time is 3 seconds, and the density is pressed to 3.2 g / cm³. 3 The material is placed in a muffle furnace for sintering. The sintering atmosphere is air, the sintering temperature is 1080℃, the heating rate is 3℃ / min, and the holding time is 3h, thus obtaining a medium-frequency low temperature coefficient nickel-copper-zinc ferrite material.

[0051] Comparative Example 1

[0052] A method for preparing medium-frequency low-temperature-coefficient nickel-copper-zinc ferrite materials includes the following steps:

[0053] (1) Weigh each raw material according to the following requirements:

[0054] Based on the total molar amount of the main ingredients as 100%, the main ingredients include the following raw materials in molar percentages: Fe2O3 41%, NiO 29.8%, CuO 5.8%, ZnO 23.4%;

[0055] Based on the total weight of the main ingredients as 100%, the additives are 0.05wt% Co2O3, 0.05wt% CaO, and 0.1wt% SiO2;

[0056] (2) First, mix the main materials, then add water to form a slurry. The solid content of the slurry is 60%. Sand mill for 45 minutes until the average particle size of the slurry is 0.8 μm. Finally, add polyvinyl alcohol solution with a mass concentration of 9% and an addition amount of 0.8% of the slurry mass. Spray dry and granulate to obtain granules. The process parameters for spray drying and granulation are: inlet temperature 350℃, outlet temperature 115℃, atomizing disc speed 7000 rpm / min, and particle size of granules 60-200 mesh with a content greater than 90%.

[0057] (3) Place the granules obtained in step (2) into a rotary kiln for pre-firing. The pre-firing atmosphere is air, the pre-firing temperature is 950℃, the pre-firing time is 45 min, and the material is cooled to 80℃ to obtain the pre-fired material.

[0058] (4) Add additives to the pre-burned material obtained in step (3), and sand mill for 120 min until the average particle size of the sand mill is 0.9 μm to obtain the sand mill.

[0059] (5) Add polyvinyl alcohol solution to the abrasive obtained in step (4). The mass concentration of the polyvinyl alcohol solution is 9%, and the amount added is 1.8% of the mass of the abrasive. Spray dry granulation is performed. The process parameters for spray drying granulation are: inlet temperature 350℃, outlet temperature 115℃, and atomizing disc speed 7000 rpm / min. Granules are obtained and passed through 80-mesh and 250-mesh sieves. The proportion of 120-200 mesh granules exceeds 75%. The granules are then pressed at a pressure of 8t / cm. 2 The pressing time is 3 seconds, and the density is pressed to 3.2 g / cm³. 3 The material is placed in a muffle furnace for sintering. The sintering atmosphere is air, the sintering temperature is 1080℃, the heating rate is 3℃ / min, and the holding time is 3h, thus obtaining a medium-frequency low temperature coefficient nickel-copper-zinc ferrite material.

[0060] Comparative Example 2

[0061] A method for preparing medium-frequency low-temperature-coefficient nickel-copper-zinc ferrite materials includes the following steps:

[0062] (1) Weigh each raw material according to the following requirements:

[0063] Based on the total molar amount of the main material being 100%, the main material includes the following raw materials in molar percentages: Fe2O3 48.5%, NiO 20.5%, CuO 6%, ZnO 25%;

[0064] Based on the total weight of the main ingredients as 100%, the additives are 0.20 wt% Co2O3, 0.03 wt% CaO, and 0.1 wt% SiO2;

[0065] (2) First, mix the main materials, then add water to form a slurry. The solid content of the slurry is 60%. Sand mill for 45 minutes until the average particle size of the slurry is 0.8 μm. Finally, add polyvinyl alcohol solution with a mass concentration of 9% and an addition amount of 0.8% of the slurry mass. Spray dry and granulate to obtain granules. The process parameters for spray drying and granulation are: inlet temperature 350℃, outlet temperature 115℃, atomizing disc speed 7000 rpm / min, and particle size of granules 60-200 mesh with a content greater than 90%.

[0066] (3) Place the granules obtained in step (2) into a rotary kiln for pre-firing. The pre-firing atmosphere is air, the pre-firing temperature is 950℃, the pre-firing time is 45 min, and the material is cooled to 80℃ to obtain the pre-fired material.

[0067] (4) Add additives to the pre-burned material obtained in step (3), and sand mill for 120 min until the average particle size of the sand mill is 0.9 μm to obtain the sand mill.

[0068] (5) Add polyvinyl alcohol solution to the abrasive obtained in step (4). The mass concentration of the polyvinyl alcohol solution is 9%, and the amount added is 1.8% of the mass of the abrasive. Spray dry granulation is performed. The process parameters for spray drying granulation are: inlet temperature 350℃, outlet temperature 115℃, and atomizing disc speed 7000 rpm / min. Granules are obtained and passed through 80-mesh and 250-mesh sieves. The proportion of 120-200 mesh granules exceeds 75%. The granules are then pressed at a pressure of 8t / cm. 2 The pressing time is 3 seconds, and the density is pressed to 3.2 g / cm³. 3 The material is placed in a muffle furnace for sintering. The sintering atmosphere is air, the sintering temperature is 1080℃, the heating rate is 3℃ / min, and the holding time is 3h, thus obtaining a medium-frequency low temperature coefficient nickel-copper-zinc ferrite material.

[0069] Comparative Example 3

[0070] A method for preparing medium-frequency low-temperature-coefficient nickel-copper-zinc ferrite materials includes the following steps:

[0071] (1) Weigh each raw material according to the following requirements:

[0072] Based on the total molar amount of the main ingredients as 100%, the main ingredients include the following raw materials in molar percentages: Fe2O3 40%, NiO 33%, CuO 5.6%, ZnO 21.4%;

[0073] Based on the total weight of the main ingredients as 100%, the additives are 0.25wt% Co2O3, 0.05wt% CaO, and 0.1wt% SiO2;

[0074] (2) First, mix the main materials, then add water to form a slurry. The solid content of the slurry is 60%. Sand mill for 45 minutes until the average particle size of the slurry is 0.8 μm. Finally, add polyvinyl alcohol solution with a mass concentration of 9% and an addition amount of 0.8% of the slurry mass. Spray dry and granulate to obtain granules. The process parameters for spray drying and granulation are: inlet temperature 350℃, outlet temperature 115℃, atomizing disc speed 7000 rpm / min, and particle size of granules 60-200 mesh with a content greater than 90%.

[0075] (3) Place the granules obtained in step (2) into a rotary kiln for pre-firing. The pre-firing atmosphere is air, the pre-firing temperature is 950℃, the pre-firing time is 45 min, and the material is cooled to 80℃ to obtain the pre-fired material.

[0076] (4) Add additives to the pre-burned material obtained in step (3), and sand mill for 120 min until the average particle size of the sand mill is 0.9 μm to obtain the sand mill.

[0077] (5) Add polyvinyl alcohol solution to the abrasive obtained in step (4). The mass concentration of the polyvinyl alcohol solution is 9%, and the amount added is 1.8% of the mass of the abrasive. Spray dry granulation is performed. The process parameters for spray drying granulation are: inlet temperature 350℃, outlet temperature 115℃, and atomizing disc speed 7000 rpm / min. Granules are obtained and passed through 80-mesh and 250-mesh sieves. The proportion of 120-200 mesh granules exceeds 75%. The granules are then pressed at a pressure of 8t / cm. 2 The pressing time is 3 seconds, and the density is pressed to 3.2 g / cm³. 3 The material is placed in a muffle furnace for sintering. The sintering atmosphere is air, the sintering temperature is 1080℃, the heating rate is 3℃ / min, and the holding time is 3h, thus obtaining a medium-frequency low temperature coefficient nickel-copper-zinc ferrite material.

[0078] Medium-frequency low-temperature coefficient nickel-copper-zinc ferrite magnetic ring samples were prepared through the processes of Examples 1-3 and Comparative Examples 1-3. The samples had an outer diameter of 25 mm, an inner diameter of 15 mm, and a height of 10 mm. The sintered magnetic rings were wound with 0.3 mm diameter, 150 cm long, three-layer insulated wire for 10 Ts, and then tested. The tests were performed using a Keysight Technologies 4294A impedance meter, primarily measuring the change in inductance with frequency; a high-low temperature oven was also used to measure the change in inductance with temperature. Specific test data are shown in Table 2.

[0079] Table 1. Raw material ratios for Examples 1-3 and Comparative Examples 1-3

[0080]

[0081] Table 2 Magnetic properties of the products from Examples 1-3 and Comparative Examples 1-3

[0082]

[0083]

[0084] Conclusion: Comparing Example 1 and Comparative Example 1, with the main formulation unchanged, reducing the Co2O3 content significantly reduces the 5M inductance of the material, and the inductance temperature change at high temperatures of 150°C and -40°C increases rapidly. This is because Co... 2+ In spinel structures, it tends to occupy octahedral B sites, and through superexchange coupling, the degree of cancellation of the anti-alignment of magnetic moments at the AB sites can be adjusted; simultaneously, Co 2+ It possesses a specific magnetocrystalline anisotropy constant, and its doping can specifically compensate for the magnetocrystalline anisotropy of nickel-zinc ferrite itself, improving the stability of magnetic permeability with temperature; finally, Co 2+ The ionic radius has good lattice matching. Appropriate doping can suppress abnormal grain growth, stabilize the spinel lattice structure, reduce lattice defects, and improve the stability of the material's inductance at frequency and temperature.

[0085] Comparing Example 2 and Comparative Example 2, with the additive scheme unchanged, increasing the Fe2O3 content significantly improved the 3MHz inductance of the material, but the 5MHz inductance decreased severely. Simultaneously, the inductance temperature change at high temperatures of 150°C and -40°C increased rapidly. This is because increasing the Fe2O3 content enhances magnetic interaction, significantly affecting the magnetocrystalline anisotropy constant K1 of the material, causing K1 to tend towards a negative value, thus increasing the inductance increase with temperature.

[0086] Comparing Example 1 and Comparative Example 3, with the additives unchanged, further reducing the Fe2O3 content resulted in a smaller rate of change of the material with frequency and temperature, but the inductance value exceeded the acceptable range and did not meet the requirements of this project. This is because further reduction of Fe2O3 leads to more defects in the material's crystal structure, introducing more impurity ions and forming void-like defects, which significantly reduces the inductance.

[0087] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications and substitutions based on the technical solutions and inventive concepts provided by the present invention should be covered within the scope of protection of the present invention.

Claims

1. A medium-frequency, low-temperature-coefficient nickel-copper-zinc ferrite material, characterized in that, Including main ingredients and additives; Based on the total molar amount of the main material being 100%, the main material comprises the following molar percentages of raw materials: Fe2O3 40.5%-42.5%, NiO 29.5%-31.5%, CuO 5.6%-6%, with the balance being ZnO; Based on the total weight of the main material as 100%, the additives are 0.15-0.3wt% Co2O3, 0.03-0.05wt% CaO, and 0.05-0.1wt% SiO2.

2. A method for preparing a medium-frequency, low-temperature-coefficient nickel-copper-zinc ferrite material, characterized in that, Includes the following steps: (1) Weigh each raw material according to the medium-frequency low-temperature coefficient nickel-copper-zinc ferrite material as described in claim 1; (2) First, mix the main materials, then add water to form a slurry, grind it, and finally add a polyvinyl alcohol solution, spray dry and granulate to obtain granules; (3) The granules obtained in step (2) are pre-fired and cooled to obtain pre-fired material; (4) Add additives to the pre-burned material obtained in step (3), and grind it to obtain abrasive material; (5) Add polyvinyl alcohol solution to the abrasive obtained in step (4), spray dry and granulate to obtain granules, press the granules and sinter them to obtain the medium frequency low temperature coefficient nickel copper zinc ferrite material.

3. The method for preparing a medium-frequency low-temperature coefficient nickel-copper-zinc ferrite material according to claim 2, characterized in that, In step (2), the solid content of the slurry is 50%-65%; the grinding time is 15-60 min; the mass concentration of the polyvinyl alcohol solution is 8%-10%, and the amount added is 0.5%-1% of the slurry mass.

4. The method for preparing a medium-frequency low-temperature coefficient nickel-copper-zinc ferrite material according to claim 2, characterized in that, In step (3), the pre-firing atmosphere is air, the pre-firing temperature is 800-1050℃, and the pre-firing time is 30-60 min.

5. The method for preparing a medium-frequency low-temperature coefficient nickel-copper-zinc ferrite material according to claim 2, characterized in that, In step (4), the grinding time is 60-150 min, and the grinding is carried out until the average particle size of the abrasive is 0.6-1.5 μm.

6. The method for preparing a medium-frequency low-temperature coefficient nickel-copper-zinc ferrite material according to claim 2, characterized in that, In step (5), the polyvinyl alcohol solution has a mass concentration of 8%-10% and is added at a rate of 0.8%-2.5% of the mass of the abrasive; the pressing pressure is 6-10 t / cm. 2 The pressing time is 1-5 seconds, and the material is pressed until the density is 2.8-3.6 g / cm³. 3 The sintering atmosphere is air, the sintering temperature is 1020-1100℃, the heating rate is 2-10℃ / min, and the holding time is 2-6h.

Images