Preparation method of self-biased ferrite material

Abstract

The invention discloses a preparation method of a self-biased ferrite material, and relates to the technical field of magnetic materials, and the method comprises the following steps: taking BaCO3, Sc2O3, CuO, ZnO and Fe2O3 as raw materials according to the following proportions: 20-30 mol% of BaCO3, 1-10 mol% of Sc2O3, 5-15 mol% of CuO, 5-15 mol% of ZnO and 69-90 mol% of Fe2O3; carrying out primary ball milling to obtain mixed powder slurry, and then carrying out ball milling and uniform mixing on the mixed powder slurry in a ball mill; pre-sintering the powder twice, and then carrying out ball milling for the second time; and preparing a pressed blank from the powder slurry by a magnetic field orientation molding technology, sintering, and quenching to room temperature to finally obtain the ion combined substitution self-biased hexagonal ferrite. The magnetization performance of the ferrite material can be remarkably improved, the ferromagnetic resonance line width is reduced, and the coercive force is enhanced. Through accurate ion substitution and magnetic field treatment, the ferrite material prepared by the invention has better microstructure and magnetic properties, and provides a new material choice for miniaturization and integration of microwave devices.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic materials, and in particular to a method for preparing a self-biased ferrite material. Background Art

[0002] With the development of modern electronic technology, microwave devices such as circulators and phase shifters are increasingly used in communications, radar and other fields. These devices usually require an external bias field to realize their functions, but the use of an external bias field limits the miniaturization and integration of the devices. Self-biased ferrite materials have attracted attention because they can provide a bias field internally, but existing materials have limitations in performance, such as insufficient magnetization, too large ferromagnetic resonance linewidth, and insufficient coercivity.

[0003] Therefore, it is of great practical significance to develop new self-biased ferrite materials to meet the needs of high-frequency, small-size, and low-loss microwave devices. Summary of the invention

[0004] The present invention aims to provide a method for preparing a self-biased ferrite material, by precisely controlling the steps of raw material ratio, ball milling, pre-sintering, doping, secondary ball milling, molding and sintering, a ferrite material with high magnetization intensity, high remanence ratio, low ferromagnetic resonance line width and high coercive force is obtained.

[0005] A method for preparing a self-biased ferrite material, the method comprising the following steps: (1) Ingredients: BaCO3, Sc2O3, CuO, ZnO, and Fe2O3 are used as raw materials, and mixed according to a proportion to obtain an initial ferrite powder, wherein the proportion is 20-30 mol% BaCO3, 1-10 mol% Sc2O3, 5-15 mol% CuO, 5-15 mol% ZnO, and 69-90 mol% Fe2O3; (2) Primary ball milling: the initial powder is mixed with deionized water in a mass ratio of 1:1-5 to obtain a mixed powder slurry, and then the mixed powder slurry is ball milled in a ball mill to be uniformly mixed; (3) Pre-burning: Dry the ball mill powder, sieve it, and then pre-burn the powder once, cool it down, and then pre-burn it again; (4) Secondary ball milling: The pre-calcined mixed powder and deionized water are mixed evenly in a mass ratio of 1:1-5, and then ball milled in a planetary ball mill to obtain a powder slurry; (5) Molding: The powder slurry is subjected to magnetic field orientation molding technology to prepare a compact, the molding magnetic field is 1-2T, and the molding pressure is 50-150MPa; (6) Sintering: The heat treatment temperature is 600-900°C, the holding time is 1-3 hours, and then it is rapidly cooled to room temperature to finally obtain ion-co-substituted self-biased hexagonal ferrite.

[0006] Furthermore, the time of the first ball milling is 1-5 hours.

[0007] Furthermore, the sintering temperature of the first pre-firing is 950-1200°C, the heating rate is 5-10°C / min, and the insulation time is 3-6 hours; the sintering temperature of the second pre-firing is 700-950°C, the heating rate is 5-10°C / min, and the insulation time is 2-4 hours.

[0008] Furthermore, the secondary ball milling time is 2-8 hours.

[0009] Furthermore, the heating rate of the sintering is 5-10°C / min.

[0010] Compared with the prior art, the preparation method of the present invention can significantly improve the magnetization performance of ferrite materials, reduce the ferromagnetic resonance line width, and enhance the coercive force. Through precise ion substitution and magnetic field treatment, the ferrite material prepared by the present invention has better microstructure and magnetic properties, providing a new material choice for the miniaturization and integration of microwave devices. Specifically, the ferrite material prepared by the present invention has the following characteristics: 1. High magnetization intensity: The saturation magnetization intensity 4πMs of the ferrite material prepared by the present invention can reach more than 5000 Gs, which meets the demand of high-frequency devices for high magnetization intensity.

[0011] 2. High remanence ratio: The remanence ratio Mr / Ms of the ferrite material prepared by the present invention can reach above 0.90, which is conducive to realizing the self-bias characteristics of the device.

[0012] 3. Low ferromagnetic resonance linewidth: The ferromagnetic resonance linewidth ΔH of the ferrite material prepared by the present invention can be controlled below 400 Oe, which helps to reduce the insertion loss of the device and improve the working frequency band of the device.

[0013] 4. High coercive force: The coercive force Hc of the ferrite material prepared by the present invention can reach more than 5000 Oe, which is conducive to maintaining the stable performance of the device. DETAILED DESCRIPTION

[0014] In specific embodiments, the preparation method of the present invention can be appropriately adjusted according to different requirements and conditions. The following are four embodiments for illustrating the preparation method of the present invention. Example 1

[0015] 1. Ingredients: Weigh the raw materials in the proportion of 25mol% BaCO3, 5mol% Sc2O3, 5mol% ZnO, 5mol% CuO, and 62mol% Fe2O3, and mix them to obtain initial powder.

[0016] 2. Primary ball milling: Mix the initial powder with deionized water in a 1:1 ratio and ball mill for 1 hour.

[0017] 3. Pre-burning: The first pre-burning temperature is 950℃, and the temperature is kept for 6 hours; after cooling, the second pre-burning temperature is 800℃, and the temperature is kept for 4 hours.

[0018] 4. Secondary ball milling: Mix the pre-calcined powder with deionized water in a ratio of 1:1 and ball mill for 4 hours to obtain a powder slurry.

[0019] 5. Molding: Molding the green compact at a pressure of 100 MPa under a 1.5 T magnetic field.

[0020] 6. Sintering: Heat treatment at 800°C for 2 hours, followed by rapid cooling to room temperature to obtain a self-biased ferrite material. Example 2

[0021] 1. Ingredients: Weigh the raw materials according to the ratio of 20mol% BaCO3, 6mol% Sc2O3, 5mol% ZnO, 5mol% CuO, and 64mol% Fe2O3, and mix them to obtain initial powder.

[0022] 2. Primary ball milling: Mix the initial powder with deionized water in a ratio of 1:3 and ball mill for 3 hours.

[0023] 3. Pre-burning: The first pre-burning temperature is 1050℃, and the temperature is kept for 5 hours; after cooling, the second pre-burning temperature is 800℃, and the temperature is kept for 3 hours.

[0024] 4. Secondary ball milling: Mix the pre-calcined powder with deionized water in a ratio of 1:3 and ball mill for 5 hours to obtain a powder slurry.

[0025] 5. Molding: Molding the green compact at a pressure of 80 MPa under a 1.5 T magnetic field.

[0026] 6. Sintering: Heat treatment at 800°C for 2 hours, followed by rapid cooling to room temperature to obtain a self-biased ferrite material. Example 3

[0027] Ingredients: weigh raw materials according to the ratio of 22 mol % BaCO3, 4 mol % Sc2O3, 3 mol % ZnO, 3 mol % CuO, and 68 mol % Fe2O3, and mix them to obtain initial powder.

[0028] 2. Primary ball milling: Mix the initial powder with deionized water in a ratio of 1:5 and ball mill for 5 hours.

[0029] 3. Pre-burning: The first pre-burning temperature is 1200℃, and the temperature is kept for 3 hours; after cooling, the second pre-burning temperature is 700℃, and the temperature is kept for 2 hours.

[0030] 4. Secondary ball milling: Mix the pre-calcined powder with deionized water in a ratio of 1:5 and ball mill for 2 hours to obtain a powder slurry.

[0031] 5. Molding: Molding the green compact at a pressure of 50 MPa under a 2T magnetic field.

[0032] 6. Sintering: Heat treatment at 700°C for 3 hours, followed by rapid cooling to room temperature to obtain a self-biased ferrite material. Example 4

[0033] 1. Ingredients: weigh the raw materials according to the ratio of 20 mol% BaCO3, 3 mol% Sc2O3, 3 mol% ZnO, 3 mol% CuO, and 71 mol% Fe2O3, and mix them to obtain initial powder.

[0034] 2. Primary ball milling: Mix the initial powder with deionized water in a ratio of 1:2 and ball mill for 4 hours.

[0035] 3. Pre-burning: The first pre-burning temperature is 1100℃, and the heat preservation is 4 hours; after cooling, the second pre-burning temperature is 750℃, and the heat preservation is 2.5 hours.

[0036] 4. Secondary ball milling: Mix the pre-calcined powder with deionized water in a ratio of 1:2 and ball mill for 3 hours to obtain a powder slurry.

[0037] 5. Molding: Molding the green compact at a pressure of 120 MPa under a 1.8 T magnetic field.

[0038] 6. Sintering: Heat treatment at 750°C for 2.5 hours, followed by rapid cooling to room temperature to obtain a self-biased ferrite material.

[0039] Through these examples, it can be seen that the preparation method of the present invention has good adaptability and adjustability, and can be adjusted according to specific application requirements and production conditions to obtain optimal magnetic properties and physical properties. These examples further verify the practicality and effectiveness of the method of the present invention, and provide strong material support for the miniaturization and integration of microwave devices.

[0040] Density(g / cm3) Saturation magnetization(Gs) Coercivity(Oe) Remanence ratio Anisotropy field (kOe) Ferromagnetic resonance linewidth(Oe) Example 1 5.24 4900 5000 0.86 13.5 420 Example 2 5.18 5050 5200 0.87 14.0 400 Example 3 5.12 5200 5500 0.89 14.5 389 Example 4 5.22 5450 5700 0.91 14.8 360 Through the above steps, the prepared ferrite material has excellent magnetic properties, including high magnetization intensity, high remanence ratio, low ferromagnetic resonance line width and high coercivity, which meets the application requirements of microwave devices. In addition, the preparation method of the present invention is simple, low-cost, easy to mass-produce, and has good industrial application prospects.

Claims

1. A method for preparing a self-biased ferrite material, characterized in that: The preparation method comprises the following steps: (1) Ingredients: BaCO3, Sc2O3, CuO, ZnO, and Fe2O3 are used as raw materials, and mixed according to a proportion to obtain an initial ferrite powder, wherein the proportion is 20-30 mol% BaCO3, 1-10 mol% Sc2O3, 5-15 mol% CuO, 5-15 mol% ZnO, and 69-90 mol% Fe2O3; (2) Primary ball milling: the initial powder is mixed with deionized water in a mass ratio of 1:1-5 to obtain a mixed powder slurry, and then the mixed powder slurry is ball milled in a ball mill to be uniformly mixed; (3) Pre-burning: Dry the ball mill powder, sieve it, and then pre-burn the powder once, cool it down, and then pre-burn it again; (4) Secondary ball milling: The pre-calcined mixed powder and deionized water are mixed evenly in a mass ratio of 1:1-5, and then ball milled in a planetary ball mill to obtain a powder slurry; (5) Molding: The powder slurry is subjected to magnetic field orientation molding technology to prepare a compact, the molding magnetic field is 1-2T, and the molding pressure is 50-150MPa; (6) Sintering: The heat treatment temperature is 600-900°C, the holding time is 1-3 hours, and then it is rapidly cooled to room temperature to finally obtain ion-co-substituted self-biased hexagonal ferrite.

2. The method for preparing the self-biased ferrite material according to claim 1, characterized in that: The time of the first ball milling is 1-5 hours.

3. The method for preparing the self-biased ferrite material according to claim 1, characterized in that: The sintering temperature of the primary pre-firing is 950-1200°C, the heating rate is 5-10°C / min, and the heat preservation time is 3-6 hours; the sintering temperature of the secondary pre-firing is 700-950°C, the heating rate is 5-10°C / min, and the heat preservation time is 2-4 hours.

4. The method for preparing the self-biased ferrite material according to claim 1, characterized in that: The time of the secondary ball milling is 2-8 hours.

5. The method for preparing the self-biased ferrite material according to claim 1, characterized in that: The heating rate of the sintering is 5-10°C / min.