High-stability gyromagnetic ferrite material, and preparation method and processing equipment thereof

Abstract

This invention discloses a method for preparing highly stable gyromagnetic ferrites, belonging to the field of magnetic material preparation technology. The method includes formulation preparation, multi-stage sand milling and granulation, molding and sintering, composite structure preparation, and precision machining steps. The formulation consists of VIII-series, IIIB-series, lanthanide-series, IVB-series, and VIIB-series metal oxides in a specific molar ratio, with rare earth nano-additives added to enhance lattice stability. Uniform slurry particle size is achieved through two-stage sand milling and spray granulation. A curved sintering process is used to control the temperature rise and oxygen content to obtain a high-density green body. A yttrium iron garnet or dysprosium iron garnet functional layer is formed on the surface of the green body by magnetron sputtering, constructing a multi-layer composite structure. Finally, a conductive modification layer is formed on the surface through integrated laser cutting and chemical mechanical polishing. The gyromagnetic ferrite material prepared by this method exhibits high saturation magnetization, low high-frequency loss, and excellent thermal stability, making it suitable for 5G communication, radar, and high-frequency microwave devices.

Description

Technical Field

[0001] This invention relates to the field of magnetic material preparation technology, specifically to a highly stable gyromagnetic ferrite material and its preparation method and processing equipment. Background Technology

[0002] Magneto-ferrites are a class of magnetic functional materials primarily composed of metal oxides, widely used in high-frequency communications, radar, microwave components, electronic power supplies, and magneto-optical devices. These materials are typically produced by sintering multiple metal oxides such as iron, cobalt, nickel, manganese, and yttrium. They possess high resistivity, low eddy current loss, and excellent frequency response characteristics, making them crucial fundamental magnetic materials for realizing 5G communications and millimeter-wave radio frequency devices.

[0003] While existing gyromagnetic ferrite materials and their preparation technologies have made some progress, they still have significant shortcomings in terms of magnetic property stability, structural consistency, and intelligent preparation processes. These shortcomings are mainly reflected in the following aspects: Existing technologies mostly employ a single system of VIII-series and IIIB-series metal oxides for composite preparation, without systematically controlling the ratio of lanthanide, IVB-series, and VIIB-series elements. This results in the instability of the material lattice during high-temperature sintering, uneven magnetic domain distribution, and consequently, large fluctuations in saturation magnetization and Curie temperature, leading to poor consistency in magnetic properties.

[0004] Traditional processes generally employ single-stage ball milling or sand milling, which results in insufficient precision in controlling the particle size of the slurry, leading to uneven density of the formed green body. At the same time, the inaccurate control of glue and solid content during spray granulation can easily cause an increase in porosity during subsequent sintering, affecting magnetic permeability and mechanical strength.

[0005] Most production lines use constant temperature sintering curves and lack segmented control for the grain growth stage. This results in a large temperature gradient and structural stress in the billet during the later stages of sintering, which can easily lead to microcracks or phase boundary discontinuities, thus affecting the high-frequency loss characteristics and service life of the product.

[0006] Traditional machining of ferrite magnets typically employs mechanical cutting and polishing methods, with machining accuracy usually above ±5μm. This results in noticeable surface microcracks and residual stress, and without the integration of surface modification technology, it is impossible to simultaneously meet the requirements for dimensional accuracy and electrical conductivity.

[0007] Existing ball mill or sand mill production lines are mostly single-machine series operation, lacking online monitoring and feedback control. Particle size detection, temperature detection, surface detection and other links rely on manual sampling inspection, resulting in poor product consistency and a defect rate of over 8%, which makes it difficult to meet the precision manufacturing needs of high-end communication components. Summary of the Invention

[0008] To address the aforementioned issues, this invention provides a highly stable gyromagnetic ferrite material, its preparation method, and processing equipment. This method enables system optimization across multiple stages, including formulation, sand milling and granulation, sintering process, structural design, and processing methods. As a result, a gyromagnetic ferrite material exhibiting low loss, high permeability, and high stability under high-frequency conditions is obtained. Furthermore, it is equipped with intelligent preparation equipment to reduce production defect rates and improve product consistency and controllability.

[0009] This invention is achieved through the following technical solution: a method for preparing highly stable gyromagnetic ferrite, comprising the following steps: (a) Formulation preparation: Weigh 40-75 parts of VIII series metal oxide, 20-50 parts of IIIB series metal oxide, 1-10 parts of lanthanide metal oxide, 1-10 parts of IVB series metal oxide, and 1-10 parts of VIIB series metal oxide in molar ratio, and add 0.1%-0.5% of rare earth nano additives, and mix the components evenly. (II) Multi-stage sand milling granulation: (a) In the first sand milling, the ratio of steel balls, raw materials and deionized water was 3.3:1:1, the sand milling speed was 100 rpm, and the process lasted for 60 minutes; (b) Add the obtained primary grinding slurry to polyvinyl alcohol glue at a mass ratio of 1:10, perform the first spray granulation, with a solid content of 50%, pass through an 80-mesh sieve, and pre-calcine at 1200℃ for 180 minutes. (c) In the second sand milling, the ratio of steel balls, pre-calcined material and deionized water is 3.3:1:0.4-1.2, the rotation speed is 150-200 rpm, and the time is 150-250 minutes, so that the slurry D50 is controlled at 0.8μm; Spray granulation is performed again, with a solid content of not less than 55%, and the granules pass through a 100-mesh sieve. (III) Molding and Curved Sintering: The granulated material is injected into the mold and extruded under a pressure of 15 MPa. Then, the temperature is increased to 1100℃ at 5-10℃ / min and held for 30 minutes. Then, the temperature is increased to 1200-1300℃ at 10℃ / min and held for 60-200 minutes. Finally, the temperature is reduced to room temperature at 3℃ / min, and the oxygen content in the furnace is maintained at 5%-8%. (iv) Preparation of composite structure: A functional layer with a thickness of 0.8-1.2 μm is deposited on the surface of the sintered green body by magnetron sputtering, wherein the functional layer is a yttrium iron garnet or a dysprosium iron garnet layer; (v) Precision machining: Cutting is performed using a laser with a wavelength of 355-532nm, followed by chemical mechanical polishing with a polishing solution containing silver ions at a concentration of 0.08-0.12mol / L, and a conductive modified layer is formed on the surface.

[0010] As a preferred technical solution, the rare earth nano-additive is gadolinium oxide nanoparticles, and the amount added is about 0.3% of the total metal oxide mass.

[0011] As a preferred technical solution, the magnetron sputtering has a radio frequency power of 200–300W and a vacuum degree better than 5 × 10⁻⁶. - ³Pa, deposition time is 10-20 minutes.

[0012] As a preferred technical solution, the polishing pressure of the chemical mechanical polishing is 0.15-0.25 MPa, the polishing speed is 70-90 rpm, and the surface roughness Ra after polishing is not greater than 0.02 μm.

[0013] The present invention provides a high-stability spin magnetite ferrite preparation device, comprising a high-speed pulper, a horizontal sand mill, a double-layer circulating tank, a secondary ball mill, and a double-layer finished product tank connected in sequence; The device is equipped with: (a) Laser particle size analyzer for real-time detection of slurry particle size; (b) An infrared thermometer for detecting sintering temperature; (c) Surface inspection instrument, used to inspect surface defects of the processed blank; If three consecutive test results fail, the system will trigger an alarm signal to suspend the production line.

[0014] As a preferred technical solution, a cooling water circulation jacket is provided between the inner and outer layers of the double-layer circulation tank to maintain the slurry temperature stability, with a temperature control range of 25±2℃.

[0015] This invention discloses a highly stable gyromagnetic ferrite material, wherein the material has a multi-layer composite structure consisting of a support layer and a functional layer. The support layer is a dense oxide matrix formed by curve sintering. The functional layer is a yttrium iron garnet layer or a dysprosium iron garnet layer. The saturation magnetization of the ferrite material is not less than 400 kA / m, the Curie temperature is not less than 450℃, and the magnetic loss at a frequency of 10 GHz is not greater than 0.005.

[0016] As a preferred technical solution, a continuous transition phase interface is formed between the support layer and the functional layer, with an interface thickness of 10-100 nm, in order to improve the interlayer bonding strength and magnetic property stability.

[0017] The present invention provides an integrated method for laser-assisted processing and chemical mechanical polishing of ferromagnetic ferrites, comprising the following steps: First, the spin magnet ferrite blank is cut and processed using an ultraviolet laser to obtain the target size; Subsequently, mechanical polishing and chemical reaction are carried out simultaneously in a chemical solution containing metal ions, so that metal ions form an embedded layer on the surface, thereby achieving simultaneous improvement in conductivity and corrosion resistance.

[0018] As a preferred technical solution, the metal ions in the chemical solution are at least one of silver ions, nickel ions, or copper ions, and the concentration is controlled within the range of 0.08 to 0.12 mol / L.

[0019] The beneficial effects of this invention are as follows: By introducing a multi-component metal oxide system and combining it with rare earth nano-additives, the lattice stability and magnetic domain uniformity of this invention are effectively improved. The saturation magnetization, Curie temperature, and high-frequency permeability of the material are significantly higher than those of the prior art, the magnetic performance fluctuation range is reduced by more than 30%, and it can still maintain low magnetic loss characteristics in high-frequency (above 10 GHz) environments; This invention employs a multi-stage sand milling granulation process to achieve dynamic control of particle size distribution. Combined with a segmented temperature control strategy in the curve sintering process, it effectively suppresses abnormal grain growth and internal stress accumulation, significantly reducing the porosity of the sintered green body. The density and uniformity are superior to those of the traditional single-stage sand milling process. This method allows the physical dimensional tolerances and density deviations of the product to be controlled within the micrometer range. The "functional layer + transition interface layer + support layer" composite structure designed in this invention tightly bonds a thin layer of yttrium iron garnet or dysprosium iron garnet to a metal oxide matrix, forming a continuous transition phase at the interface layer, which significantly reduces the interfacial magnetoresistance and counter-magnetic field effect. This structure balances low-loss performance and mechanical stability at high frequencies, enabling the material to simultaneously meet the application requirements of microwave devices and high-frequency magnetic cores. The integrated laser-assisted cutting and chemical mechanical polishing-metal ion modification process of this invention achieves simultaneous control of machining and surface functionalization, with a product dimensional accuracy of ±0.1μm and a surface roughness Ra≤0.02μm. The conductive layer formed by the metal ion intercalation reaction further improves the conductivity and corrosion resistance of the material surface, providing an excellent foundation for subsequent coating, welding, and electromagnetic shielding. The preparation equipment of this invention integrates particle size detection, temperature detection, and surface detection modules, enabling online real-time monitoring and adaptive process adjustment. When continuous abnormalities occur in the detection results, an automatic alarm is triggered and process parameters are adjusted to avoid batch defects caused by human error. Actual test results show that the defect rate of the system of this invention can be reduced from over 8% in the original process to below 2%, and the production cycle is shortened by approximately 25%. This invention not only improves performance at the material level, but also establishes a systematic technical framework for process control, equipment integration, and post-processing integration, forming a closed-loop control model covering the entire chain from raw material formulation and manufacturing to finished product testing. This model effectively reduces reliance on manual labor and improves consistency, providing a stable and reliable technical path for the manufacturing of high-end magnetic components. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Fig. 1 This is a block diagram of the overall structure of the high-stability gyromagnetic ferrite preparation system of the present invention; Fig. 2 This is a schematic diagram of the interlayer structure of the multilayer composite gyromagnetic ferrite material of the present invention. Detailed Implementation

[0022] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0023] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features for a similar purpose, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0024] like Figs. 1-2 As shown, this invention proposes a highly stable gyromagnetic ferrite material, its preparation method, and processing equipment, belonging to the field of magnetic functional material preparation and processing technology. Through synergistic improvements in multiple aspects, including formulation system, powder preparation, sintering process, composite structure design, precision machining, and automated equipment control, the gyromagnetic ferrite material achieves high permeability, low loss, and high-temperature stability in high-frequency communication and microwave devices.

[0025] The technical solution provided by this invention covers the entire process from raw material preparation, slurry refinement, molding and sintering, structural composite, surface processing to finished product testing, ensuring the uniformity of material properties and the controllability of the production process.

[0026] In the implementation of this invention, the raw material formulation is prepared first. The performance of gyromagnetic ferrite materials is closely related to the composition and proportion of their metal oxides.

[0027] This invention constructs a stable crystal lattice system by introducing various metal oxides from different families. VIII-series metal oxides (such as iron, cobalt, nickel, etc.) are used as the main magnetic components, IIIB-series metal oxides (such as yttrium oxide, aluminum oxide, etc.) are used to improve the structural integrity of the crystal lattice, lanthanide metal oxides (such as lanthanum oxide, cerium oxide, neodymium oxide, etc.) play a role in regulating grain boundary energy, IVB-series metal oxides (such as titanium oxide, zirconium oxide, etc.) enhance the thermal stability of the material, and VIIB-series metal oxides (such as manganese oxide) optimize the magnetic domain structure and magnetic permeability.

[0028] The formulation further incorporates trace amounts of rare earth nano-additives, using nano-sized powders such as gadolinium oxide, erbium oxide, or praseodymium oxide, with a particle size controlled below 50 nanometers, to enhance grain boundary bonding energy and magnetization. The synergistic effect of the multi-metal oxide system in this invention leads to a balance between lattice constant and cation distribution, effectively avoiding lattice distortion and stress concentration problems that occur in single-system materials during high-temperature sintering, thereby improving the magnetic stability of the material.

[0029] During the raw material mixing process, a precision weighing device is used to quantitatively weigh each metal oxide powder, and a planetary mixer is used for preliminary dry mixing to ensure uniform distribution of the raw materials. Subsequently, an appropriate amount of deionized water is added to the mixing system to form a slurry with a certain solid content, and pre-dispersed rare earth nano-additives are added under stirring.

[0030] To prevent nanoparticle aggregation, an ultrasonic disperser is used to subject the slurry to high-frequency oscillation, ensuring that the nano-additives are uniformly distributed among the metal oxide particles. This process plays a crucial role in the formation of grain boundary phases during subsequent sintering, significantly reducing deviations in grain size distribution and thus improving material consistency.

[0031] The powder refining process of this invention employs a multi-stage sand milling process. The first stage of sand milling primarily achieves the crushing and preliminary dispersion of coarse powder particles, while the second stage of sand milling performs fine particle size control. High-purity zirconia beads are used as the milling media, with a particle size controlled between 0.5 and 1.0 mm to avoid impurity contamination. During the sand milling process, by adjusting the rotation speed and time, the average particle size of the slurry is gradually refined from the micrometer level to the submicrometer level.

[0032] This invention utilizes a two-stage sand milling process to achieve a more concentrated particle size distribution in the slurry, stabilizing the D50 value at approximately 0.8 micrometers and the particle size distribution index at less than 1.6, ensuring dense packing of particles during sintering. After sand milling, the slurry undergoes high-speed centrifugation to degas and eliminate residual air bubbles, preventing the formation of voids during molding.

[0033] The granulation process employs spray granulation. The sand-milled slurry is mixed with a certain proportion of polyvinyl alcohol (PVA) adhesive, with the adhesive content controlled at 5%–10% of the slurry mass to obtain appropriate adhesion.

[0034] The inlet air temperature of the spray granulator is controlled at 150℃~180℃, and the outlet air temperature is about 90℃~100℃, producing spherical granules with good flowability and a moisture content of less than 1%. The granulated powder is then passed through a 100-mesh sieve to ensure a consistent particle size distribution.

[0035] The powder was then pre-fired in a bell-type pre-firing furnace at approximately 1200°C for 3 hours to remove organic matter and promote the initial formation of the crystal lattice. The pre-fired powder had a uniform color and firm particles, providing a good physical basis for subsequent molding.

[0036] The forming process employs a mold pressing technique. Using a stainless steel hard mold, pre-fired powder is loaded into the mold cavity, and a pressure of 15 MPa is applied to form a green body, typically a circular sheet with a diameter of 20 mm and a thickness of 5 mm. During the forming process, a vibration device assists in the material distribution to ensure uniform pressing density and prevent internal delamination or cracks. The formed green body is then naturally dried or low-temperature dried to reduce the moisture content to below 0.2% to prevent cracking due to gas expansion during sintering.

[0037] The sintering process employs a curve-based temperature control method, replacing the traditional isothermal process with a segmented temperature curve. The heating rate is kept relatively slow in the low-temperature stage to promote the decomposition of organic matter and the expulsion of gases; the heating rate is accelerated in the medium-temperature stage to achieve lattice growth; and the heating rate is further reduced in the high-temperature stage to suppress abnormal grain growth.

[0038] The entire process is carried out in an atmosphere with adjustable oxygen partial pressure, and the oxygen content is controlled between 5% and 8%. The maximum sintering temperature is 1250℃, and after holding at that temperature for 2 hours, it is cooled to room temperature at a slow rate. This curved sintering process can effectively eliminate internal thermal stress, promote grain boundary densification, and reduce the formation of microcracks caused by temperature gradients. The sintered green body has a uniform color, no obvious sintering scars on the surface, and a density close to or greater than 98% of the theoretical value.

[0039] After the sintered green body is completed, this invention constructs a multilayer composite structure on its surface using physical vapor deposition. First, the green body is loaded into a vacuum magnetron sputtering apparatus, where a vacuum level better than 5 × 10⁻⁶ is maintained. - Sputter deposition was carried out in an environment of ³Pa.

[0040] Yttrium iron garnet or dysprosium iron garnet was used as the target material, and the radio frequency power was controlled at approximately 250W. The deposition time was 10–20 minutes to form a functional layer with a thickness of approximately 1 micrometer. The functional layer and the substrate were bonded to the substrate through ion energy control, which caused local interdiffusion of atoms at the interface to form a continuous bonding layer, thereby significantly reducing the interfacial magnetoresistance.

[0041] The multilayer composite structure design of this invention introduces an intermediate transition interface between the support layer and the functional layer, which effectively suppresses the magnetic field boundary reflection effect and improves the stability of the magnetic permeability response at high frequencies.

[0042] The composite blank processing of this invention employs laser-assisted precision cutting technology. A 355 nm ultraviolet laser is used to cut the blank, with the laser energy density controlled within an appropriate range to avoid the expansion of the heat-affected zone. During the cutting process, the scanning path is adjusted by a CNC system to achieve high-precision machining of the outer contour and inner holes, with a machining accuracy of ±0.1 micrometers. The non-contact processing method of laser cutting effectively avoids mechanical stress transmission and edge chipping, ensuring material integrity.

[0043] After laser processing, the surface of the blank is smoothed using an integrated chemical mechanical polishing process. The polishing medium is a composite polishing slurry containing metal ions, preferably a solution containing silver, nickel, or copper ions, with the ion concentration controlled at approximately 0.1 mol / L.

[0044] The polishing process combines mechanical grinding with a chemical reaction, achieving uniform removal of the atomic layer on the material surface at the microscopic level. This process not only reduces surface roughness to below Ra 0.02 micrometers but also forms a metal ion-intercalating modified layer on the surface. This conductive modified layer enhances the surface's conductivity and corrosion resistance, while also helping to suppress surface static electricity buildup and improve electromagnetic compatibility.

[0045] To achieve automation and high consistency in the production process, this invention employs an intelligent preparation equipment system. This system comprises a high-speed pulper, a horizontal sand mill, a double-layer circulating tank, a secondary ball mill, and a double-layer finished product tank, connected sequentially. Each unit is interconnected via stainless steel pipelines, forming a closed production chain. The system integrates sensors such as a laser particle size analyzer, an infrared thermometer, and a surface inspection instrument to achieve real-time monitoring of pulp particle size, temperature, and the surface condition of the finished product.

[0046] Data is aggregated through a central control system. When three samples are detected consecutively exceeding the set standard, the system automatically triggers an alarm and suspends the process, allowing the control program to optimize and readjust parameters. This closed-loop control mechanism significantly reduces reliance on manual labor and improves the reliability of the production line and product consistency.

[0047] During equipment operation, the double-layer circulating tank structure is used to maintain the stability of the slurry temperature and particle size. The inner layer of the tank is the slurry channel, and the outer layer is a circulating cooling water jacket. The constant temperature water system maintains the slurry temperature at 25±2℃ to prevent temperature rise during the grinding process from causing changes in slurry viscosity. All stirring and conveying units are driven by variable frequency motors. The control system can automatically adjust the speed according to the detection data to match the slurry state, thereby maintaining the stability of grinding efficiency and particle size distribution.

[0048] The ferromagnetic ferrite material prepared by this invention has been tested and found to have a saturation magnetization of over 400 kA / m, a Curie temperature greater than 450℃, and a magnetic loss coefficient of less than 0.005 at a frequency of 10 GHz.

[0049] The testing methods include measuring the magnetization curve using a vibrating sample magnetometer, measuring the Curie temperature using a thermal analyzer, and testing high-frequency loss parameters using a network analyzer.

[0050] The results show that the material has excellent magnetic response stability and low loss characteristics under high frequency operating conditions, which can meet the performance requirements of devices such as 5G communication systems, millimeter-wave circulators and isolators.

[0051] In the production line of this invention, the performance testing unit is located at the output end and is used to test the magnetic properties and structural consistency of each batch of products.

[0052] This unit includes a permeability measurement module, a dielectric loss analysis module, and a three-dimensional morphology inspection module. The test data is uploaded to a central database in real time to generate product traceability information and quality statistical reports. The system can adaptively adjust to process differences between different formulations or batches through parameter learning algorithms, achieving cross-batch quality control.

[0053] The preparation equipment of this invention also has safety and maintenance functions. The system is equipped with multiple temperature and pressure sensors. When the equipment operating temperature exceeds the set threshold or the pressure is abnormal, the control system immediately stops operation and issues an alarm. The equipment adopts a modular structure design, which facilitates maintenance and upgrades. The control interface conforms to Industry 4.0 standards and can achieve interconnection with the production management system.

[0054] Through the above-described scheme, this invention achieves intelligent and precise control over the entire process of developing gyromagnetic ferrite materials, from formulation design to finished product testing. Parameter matching between each stage is optimized through control algorithms, resulting in stable and repeatable product performance. The multi-layered composite design of the material structure balances magnetic properties, mechanical strength, and surface functionality, providing a highly reliable material foundation for high-frequency communication and microwave technologies.

[0055] Through repeated experiments, the preparation method of this invention has been verified to operate stably on an industrial scale, with batch production consistency better than ±2% and production efficiency increased by more than 25%. Compared with traditional processes, this invention not only reduces manual intervention but also effectively reduces resource waste and environmental emissions. The equipment system can adjust the sand milling time, sintering curve, and sputtering process parameters according to different product specifications, enabling the co-production of multiple product models and possessing high flexibility in manufacturing.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived without inventive effort should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for preparing a highly stable gyromagnetic ferrite, characterized in that, Includes the following steps: (a) Formulation preparation: Weigh 40-75 parts of VIII series metal oxide, 20-50 parts of IIIB series metal oxide, 1-10 parts of lanthanide metal oxide, 1-10 parts of IVB series metal oxide, and 1-10 parts of VIIB series metal oxide in molar ratio, and add 0.1%-0.5% of rare earth nano additives, and mix the components evenly. (II) Multi-stage sand milling granulation: (a) In the first sand milling, the ratio of steel balls, raw materials and deionized water was 3.3:1:1, the sand milling speed was 100 rpm, and the process lasted for 60 minutes; (b) Add the obtained primary grinding slurry to polyvinyl alcohol glue at a mass ratio of 1:10, perform the first spray granulation, with a solid content of 50%, pass through an 80-mesh sieve, and pre-calcine at 1200℃ for 180 minutes. (c) In the second sand milling, the ratio of steel balls, pre-calcined material and deionized water is 3.3:1:0.4-1.2, the rotation speed is 150-200 rpm, and the time is 150-250 minutes, so that the slurry D50 is controlled at 0.8μm; Spray granulation is performed again, with a solid content of not less than 55%, and the granules pass through a 100-mesh sieve. (III) Molding and Curved Sintering: The granulated material is injected into the mold and extruded under a pressure of 15 MPa. Then, the temperature is increased to 1100℃ at 5-10℃ / min and held for 30 minutes. Then, the temperature is increased to 1200-1300℃ at 10℃ / min and held for 60-200 minutes. Finally, the temperature is reduced to room temperature at 3℃ / min, and the oxygen content in the furnace is maintained at 5%-8%. (iv) Preparation of composite structure: A functional layer with a thickness of 0.8-1.2 μm is deposited on the surface of the sintered green body by magnetron sputtering, wherein the functional layer is a yttrium iron garnet or a dysprosium iron garnet layer; (v) Precision machining: Cutting is performed using a laser with a wavelength of 355-532nm, followed by chemical mechanical polishing with a polishing solution containing silver ions at a concentration of 0.08-0.12mol / L, and a conductive modified layer is formed on the surface.

2. The method for preparing highly stable gyromagnetic ferrite according to claim 1, characterized in that: The rare earth nano-additive is gadolinium oxide nanoparticles, and the amount added is about 0.3% of the total metal oxide mass.

3. The method for preparing highly stable gyromagnetic ferrite according to claim 1, characterized in that: The magnetron sputtering has a radio frequency power of 200–300 W and a vacuum level better than 5 × 10⁻⁶ W. - ³Pa, deposition time is 10-20 minutes.

4. The method for preparing highly stable gyromagnetic ferrite according to claim 1, characterized in that: The chemical mechanical polishing process uses a polishing pressure of 0.15–0.25 MPa and a polishing speed of 70–90 rpm, resulting in a surface roughness Ra of no more than 0.02 μm after polishing.

5. A device for preparing highly stable gyromagnetic ferrite. Its features are, It includes a high-speed pulper, a horizontal sand mill, a double-layer circulating tank, a secondary ball mill, and a double-layer finished product tank connected in sequence; The device is equipped with: (a) Laser particle size analyzer for real-time detection of slurry particle size; (b) An infrared thermometer for detecting sintering temperature; (c) Surface inspection instrument, used to inspect surface defects of processed blanks; If three consecutive test results fail, the system will trigger an alarm signal to suspend the production line.

6. The method for preparing highly stable gyromagnetic ferrite according to claim 5, characterized in that: The double-layer circulating tank is provided with a cooling water circulation jacket between the inner and outer layers to maintain the slurry temperature stability, with a temperature control range of 25±2℃.

7. A highly stable gyromagnetic ferrite material, characterized in that, The material has a multi-layered composite structure consisting of a support layer and a functional layer. The support layer is a dense oxide matrix formed by curve sintering. The functional layer is a yttrium iron garnet layer or a dysprosium iron garnet layer. The saturation magnetization of the ferrite material is not less than 400 kA / m, the Curie temperature is not less than 450℃, and the magnetic loss at a frequency of 10 GHz is not greater than 0.

005.

8. The high-stability gyromagnetic ferrite material according to claim 7, characterized in that: A continuous transition phase interface is formed between the support layer and the functional layer, with an interface thickness of 10–100 nm, to improve the interlayer bonding strength and magnetic property stability.

9. A method for integrating laser-assisted processing and chemical mechanical polishing of spin-magnetic ferrites, characterized in that, Includes the following steps: First, the spin magnet ferrite blank is cut and processed using an ultraviolet laser to obtain the target size; Subsequently, mechanical polishing and chemical reaction are carried out simultaneously in a chemical solution containing metal ions, so that metal ions form an embedded layer on the surface, thereby achieving simultaneous improvement in conductivity and corrosion resistance.

10. The integrated method according to claim 9, characterized in that: The metal ions in the chemical solution are at least one of silver ions, nickel ions, or copper ions, and the concentration is controlled within the range of 0.08 to 0.12 mol / L.

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