Magnetic diamond composite material and preparation method and application thereof

Abstract

The invention belongs to the field of functional diamond material synthesis and magnetic superhard material preparation, and particularly relates to a magnetic diamond composite material and a preparation method and application thereof. The preparation process of the composite material comprises the following steps: grinding and uniformly mixing a magnetic particle material and a diamond superhard matrix material, and drying to obtain a precursor material; and the precursor material is treated for 5-120 min under the conditions of 5-20 GPa and 1000-2000 DEG C, and the magnetic diamond composite material is obtained after the obtained product is subjected to surface polishing treatment. According to the preparation method, the compressive strength and wear resistance of the magnetic material are remarkably improved, the obtained composite material is excellent in structural integrity and has magnetism, and the Vickers hardness of the composite material reaches 40 GPa or above.

Description

Technical Field

[0001] This invention belongs to the field of functional diamond material synthesis and magnetic superhard material preparation, specifically relating to a magnetic diamond composite material, its preparation method, and its application. Background Technology

[0002] Magnetic materials, as core strategic foundational materials supporting the upgrading of modern industrial systems and high-tech industries, have applications covering numerous fields such as energy and power, electronic information, high-end manufacturing, new energy, biomedicine, aerospace, and national defense. Their performance directly determines the core competitiveness of high-end equipment. With the optimization of magnetic material performance and the development of new magnetic materials such as rare-earth permanent magnets, spintronic materials, and nanomagnetic materials, the application scenarios of magnetic materials are continuously expanding towards extreme working conditions such as high temperature, low temperature, strong vibration, and high corrosion, as well as towards precision and multi-functionality. However, despite the phased progress in the research and development of existing magnetic materials, there are still core technological bottlenecks in their synthesis processes and performance synergy that are difficult to overcome, becoming a key weakness restricting the performance upgrade of high-end equipment. For example, ferrite soft magnetic materials mainly rely on traditional preparation methods such as solid-state sintering, sol-gel, and hydrothermal synthesis. These methods suffer from low densification and poor temperature field uniformity, and are prone to process defects such as grain boundary micropores during the sintering stage. In addition, composite soft magnetic materials such as particulate composite magnets traditionally rely on preparation methods such as magnetron sputtering, sol-gel coating, and conventional powder metallurgy sintering. These methods have insufficient ability to control the interfacial reaction between the magnetic functional phase and the matrix, and cannot achieve a strong atomic-level bond at the interface during the preparation process. They also cannot eliminate the interfacial micro-gap and micro-defects introduced during coating and sintering, resulting in an interfacial bonding strength between the magnetic functional phase and the matrix of only 10 MPa to 20 MPa. At high temperatures above 200 ℃ or under temperature cycling conditions, the interfacial defects introduced during preparation will continue to expand, eventually leading to interfacial peeling and functional phase shedding, causing a significant decrease in the magnetic properties of the material, which cannot meet the requirements of high-end equipment for long-term stable operation of magnetic materials. Summary of the Invention

[0003] Based on the above technical problems, this invention provides a method for preparing magnetic diamond composite materials. By combining magnetic particles with a diamond superhard matrix and optimizing the interface, it specifically solves the three core problems of existing traditional magnetic materials: "poor temperature stability, weak mechanical properties, and insufficient interfacial bonding".

[0004] The technical solution of this invention is: This invention provides a method for preparing a magnetic diamond composite material, comprising the following steps: The magnetic particle material is ground and mixed with the diamond superhard matrix material, and then dried to obtain the precursor material. The precursor material was treated at 5 GPa~20 GPa and 1000 ℃~2000 ℃ for 5 min~120 min, and the resulting product was then surface polished to obtain the magnetic diamond composite material.

[0005] As a preferred embodiment of the present invention, the processing conditions of the precursor are: 12 GPa~20 GPa, 1000℃~2000℃ for 5 min~120 min.

[0006] In a preferred embodiment of the present invention, the mass ratio of the magnetic particle material to the diamond superhard matrix material is 1~9:1~999.

[0007] In a preferred embodiment of the present invention, the magnetic particle material includes at least one ferrite soft magnetic material.

[0008] More preferably, the magnetic particle material is selected from any one or a combination of several of magnesium ferrite, zinc ferrite, manganese ferrite, nickel ferrite, and iron(III) oxide.

[0009] More preferably, the size of the magnetic particle material is 5 nm to 50 μm.

[0010] In a preferred embodiment of the present invention, the diamond superhard matrix material is selected from diamond phase materials or graphite phase materials.

[0011] More preferably, the diamond phase material is selected from any one of nano diamond powder, micron diamond powder, nanotwinned diamond, and porous diamond; the graphite phase material is selected from any one of flake graphite, nano graphite powder, single-walled carbon nanotubes, multi-walled carbon nanotubes, fullerene, graphene, glassy carbon, and amorphous carbon.

[0012] More preferably, the diamond phase material has a size of 5 nm to 1000 nm, and the graphite phase material has a size of 5 nm to 1000 nm.

[0013] In a preferred embodiment of the present invention, the grinding is performed using an agate mortar and pestle or a ball mill.

[0014] The present invention also provides a magnetic diamond composite material prepared according to any of the above methods.

[0015] This invention also provides an application of the magnetic diamond composite material in energy and power, electronic information, high-end manufacturing, new energy, biomedicine, aerospace, and national defense.

[0016] As a preferred embodiment of the present invention, the magnetic diamond composite material is used to prepare core components for extreme environment magnetic sensors, magnetic core materials for high temperature and high frequency electronic devices, high-efficiency magnetoelectric conversion components for new energy equipment, or anti-interference magnetic shielding components for military and special equipment.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention utilizes high temperature and high pressure to achieve in-situ composite formation of magnetic particles with a diamond superhard matrix, realizing the synergistic integration of diamond's intrinsic properties of "superhardness and wear resistance, high thermal conductivity, wide temperature range stability, and chemical inertness" with the magnetic properties of the magnetic material. The magnetic diamond composite material synthesized using the method provided by this invention exhibits excellent structural integrity and magnetism, such as a saturation magnetization of 0.5 emu / g and a remanence of 0.2 emu / g, with stable and controllable magnetic properties. Furthermore, the Vickers hardness of this magnetic diamond composite material exceeds 40 GPa, falling into the category of superhard materials. It can be used to prepare core components for extreme environment magnetic sensors, magnetic core materials for high-temperature, high-frequency electronic devices, high-efficiency magnetoelectric conversion components for new energy equipment, or anti-interference magnetic shielding components for military and special equipment. Attached Figure Description

[0018] Figure 1 Optical image of a polished cross-section of a magnetic diamond composite material; Figure 2 Optical image of the polished side of a magnetic diamond composite material; Figure 3 Scanning electron microscope image of the magnetic diamond composite material after synthesis and polishing; Figure 4 Vickers hardness test images of the synthesized magnetic diamond composite material; Figure 5 Magnetic measurement results after the synthesis of magnetic diamond composite material. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0020] This invention provides a method for preparing a magnetic diamond composite material, comprising the following steps: The magnetic particle material is ground and mixed with the diamond superhard matrix material, and then dried to obtain the precursor material. The precursor material was treated at 5 GPa~20 GPa and 1000 ℃~2000 ℃ for 5 min~120 min, and the resulting product was then surface polished to obtain the magnetic diamond composite material.

[0021] This invention innovatively proposes a magnetic diamond composite material system, which uses high temperature and high pressure to in-situ composite magnetic particles with a diamond superhard matrix. This achieves the synergistic integration of the intrinsic properties of diamond ("superhard and wear-resistant, high thermal conductivity, wide temperature stability, and chemical inertness") with the magnetic functions of the magnetic material, demonstrating groundbreaking technical advantages and providing a brand-new material solution for the performance upgrade of high-end equipment.

[0022] Diamond, as the best-known superhard material in terms of comprehensive performance, precisely complements the technical pain points of magnetic materials with its intrinsic properties: its Vickers hardness is as high as 70 GPa~100 GPa, which is twice that of cubic boron nitride and five to ten times that of cemented carbide; its compressive strength is ≥200 GPa, which is more than ten times that of high-strength steel; and it is not prone to plastic deformation in high-temperature and high-pressure environments. Its wear resistance is 100 to 1000 times that of cemented carbide, and its service life can be increased by an order of magnitude under extreme working conditions such as high-speed cutting and heavy-duty wear. More importantly, diamond has a room temperature thermal conductivity of 2000 W / (m·K)~2200 W / (m·K) and excellent thermal stability, which makes it less prone to thermal stress cracking due to sudden temperature changes. At the same time, it has excellent chemical inertness and resistance to acids and alkalis and corrosion.

[0023] The preparation method of the magnetic diamond composite material described in this invention is crucial, with the selection of magnetic particle material and diamond superhard matrix material being the core steps. Controlling the mass ratio of the two materials is one of the key factors determining the final performance of the magnetic diamond composite material. It is essential to avoid an excessively high mass ratio of magnetic particle material, as this significantly impairs the bonding effect after the graphite phase transformation into diamond and weakens the polymerization strength of diamond micropowder after high-temperature and high-pressure sintering, ultimately leading to a deterioration in the mechanical properties of the magnetic diamond composite material. Therefore, this invention controls the mass ratio of magnetic particle material within the range of 0.1 wt.% to 10 wt.%.

[0024] When selecting magnetic particle materials, it is essential to ensure that the materials possess excellent magnetic properties and stability under high temperature and pressure. The magnetic particle materials must maintain their crystal structure intact and avoid phase transitions or lattice distortions under the extreme high temperature and pressure conditions required for the synthesis of magnetic diamond composite materials. In some embodiments, the selection of magnetic particle materials includes at least one ferrite soft magnetic material. Their sizes range from 5 nm to 50 μm; if there are special preparation requirements, micron-sized magnetic particle materials can be used.

[0025] When selecting a diamond superhard matrix material, it is necessary to ensure that the material can maintain its diamond phase or transform into a diamond phase after being subjected to high temperature and high pressure conditions. In some embodiments, the diamond superhard matrix material can be a diamond phase material, such as diamond microcrystals, with a size ranging from 5 nm to 1000 nm; or a graphite phase material, such as flake graphite, with a size ranging from 5 nm to 1000 nm; if there are special preparation requirements for the material, a micron-sized diamond phase superhard matrix material can be selected.

[0026] In some embodiments, the mass ratio of magnetic particle material to diamond superhard matrix material is 1~9:1~999.

[0027] In some implementations, anhydrous ethanol can be added and the two materials can be thoroughly ground and mixed using an agate mortar and pestle.

[0028] In some implementations, a ball mill is used to thoroughly grind and mix the two materials. The methods for grinding and mixing the two materials include, but are not limited to, grinding with an agate mortar and pestle and grinding with a ball mill. Grinding with an agate mortar and pestle prevents impurities from falling off and causing contamination, provides gentle and controllable grinding force, protects the integrity of the magnetic particles and the diamond lattice, and is simple to operate, making it suitable for small-batch experimental research and development. Grinding with a ball mill is highly efficient, effectively breaks up powder agglomerates, and precisely controls particle size and dispersion uniformity, making it suitable for large-scale production. When synthesizing magnetic diamond composite materials, a suitable grinding method can be selected according to specific requirements.

[0029] In the drying step, the drying temperature needs to be maintained within the temperature range where the magnetic particle material undergoes a phase transition. Preferably, the precursor material can be dried in a vacuum atmosphere.

[0030] In the preparation method of this invention, after selecting suitable magnetic particle materials and grinding and mixing them with diamond superhard matrix materials, the control of pressure and temperature is also a core step. In some embodiments, the pressure is controlled within the range of 5 GPa to 20 GPa, the temperature within the range of 1000 ℃ to 2000 ℃, and the holding time within the range of 5 min to 120 min. The choice of pressure depends on the type of magnetic particle material and diamond superhard matrix material, while the temperature changes accordingly with the pressure. For example, when the diamond superhard matrix material is selected from graphite phase materials, magnetic diamond composite materials cannot be synthesized at a pressure of 5 GPa, but can be synthesized at a pressure above 12 GPa; however, when the diamond superhard matrix material is selected from diamond phase materials, a higher pressure is not required, and magnetic diamond composite materials can be synthesized at 5 GPa.

[0031] Furthermore, this invention can flexibly select magnetic particles of different types, such as paramagnetic, ferromagnetic, ferrimagnetic, and antiferromagnetic, and suitable diamond superhard matrix materials, according to different magnetic diamond superhard material properties and target application requirements. By precisely adjusting the relative mass ratio of the two materials, the magnetic characteristics and superhard mechanical properties of the composite material can be directionally controlled, ultimately enabling the product to obtain the optimal comprehensive performance suitable for the target application scenario.

[0032] Example 1 A method for preparing a magnetic diamond composite material, referenced Figures 1-2 This includes the following steps: (1) Weigh 1 g of iron oxide and nano-graphite powder at a mass ratio of 1:9, add anhydrous ethanol, and grind thoroughly for 30 min using an agate mortar to obtain a high-temperature and high-pressure synthesis precursor material; wherein the particle size of iron oxide is 20 nm and the particle size of nano-graphite powder is 600 nm. (2) The high-temperature and high-pressure synthesis precursor material obtained in step (1) is dried in a vacuum atmosphere at 100 °C; (3) The precursor material dried in step (2) is filled into the high temperature and high pressure synthesis assembly cavity, and then placed in the high temperature and high pressure synthesis equipment. The pressure is set to 13 GPa and the temperature is 1500 ℃. The temperature and pressure are maintained for 15 min to obtain the magnetic diamond composite material.

[0033] Example 2 A method for preparing a magnetic diamond composite material, referenced Figures 1-2 This includes the following steps: (1) Weigh 1 g of iron oxide and nano-graphite powder at a mass ratio of 1:999, add anhydrous ethanol, and grind thoroughly for 30 min using an agate mortar to obtain a high-temperature and high-pressure synthesis precursor material; wherein the particle size of iron oxide is 20 nm and the particle size of nano-graphite powder is 600 nm. (2) The high-temperature and high-pressure synthesis precursor material obtained in step (1) is dried in a vacuum atmosphere at 100 °C; (3) The precursor material dried in step (2) is filled into the high temperature and high pressure synthesis assembly cavity, and then placed in the high temperature and high pressure synthesis equipment. The pressure is set to 13 GPa and the temperature is 1500 ℃. The temperature and pressure are maintained for 15 min to obtain the magnetic diamond composite material.

[0034] Example 3 A method for preparing a magnetic diamond composite material, referenced Figures 1-2 This includes the following steps: (1) Weigh 1 g of iron oxide and nano-graphite powder at a mass ratio of 1:9, add anhydrous ethanol, and grind thoroughly for 30 min using an agate mortar to obtain a high-temperature and high-pressure synthesis precursor material; wherein the particle size of iron oxide is 1000 nm and the particle size of nano-graphite powder is 5 nm. (2) The high-temperature and high-pressure synthesis precursor material obtained in step (1) is dried in a vacuum atmosphere at 100 °C; (3) The precursor material dried in step (2) is filled into the high temperature and high pressure synthesis assembly cavity, and then placed in the high temperature and high pressure synthesis equipment. The pressure is set to 13 GPa and the temperature is 1500 ℃. The temperature and pressure are maintained for 15 min to obtain the magnetic diamond composite material.

[0035] Example 4 A method for preparing a magnetic diamond composite material, referenced Figures 1-2 This includes the following steps: (1) Weigh 1 g of nickel ferrite and multi-walled carbon nanotubes at a mass ratio of 1:9, add anhydrous ethanol, and grind them thoroughly for 30 min using an agate mortar to obtain a high-temperature and high-pressure synthesis precursor material; wherein the particle size of nickel ferrite is 5 nm and the particle size of multi-walled carbon nanotubes is 1000 nm. (2) The high-temperature and high-pressure synthesis precursor material obtained in step (1) is dried in a vacuum atmosphere at 100 °C; (3) The precursor material dried in step (2) is filled into the high temperature and high pressure synthesis assembly cavity, and then placed in the high temperature and high pressure synthesis equipment. The pressure is set to 13 GPa and the temperature is 1500 ℃. The temperature and pressure are maintained for 15 min to obtain the magnetic diamond composite material.

[0036] Example 5 A method for preparing a magnetic diamond composite material, referenced Figures 1-2 This includes the following steps: (1) Weigh 1 g of iron oxide and nano diamond powder at a mass ratio of 1:9, add anhydrous ethanol, and grind thoroughly for 30 min using an agate mortar to obtain a high-temperature and high-pressure synthesis precursor material; wherein the particle size of iron oxide is 20 nm and the particle size of nano diamond powder is 600 nm. (2) The high-temperature and high-pressure synthesis precursor material obtained in step (1) is dried in a vacuum atmosphere at 100 °C; (3) The precursor material dried in step (2) is filled into the high temperature and high pressure synthesis assembly cavity, and then placed in the high temperature and high pressure synthesis equipment. The pressure is set to 5 GPa and the temperature is 2000 ℃. The temperature and pressure are maintained for 80 min to obtain the magnetic diamond composite material.

[0037] Example 6 A method for preparing a magnetic diamond composite material, referenced Figures 1-2 This includes the following steps: (1) Weigh 1 g of iron oxide and nano diamond powder at a mass ratio of 1:9, add anhydrous ethanol, and grind thoroughly for 30 min using an agate mortar to obtain a high-temperature and high-pressure synthesis precursor material; wherein the particle size of iron oxide is 20 nm and the particle size of nano diamond powder is 600 nm. (2) The high-temperature and high-pressure synthesis precursor material obtained in step (1) is dried in a vacuum atmosphere at 100 °C; (3) The precursor material dried in step (2) is filled into the high temperature and high pressure synthesis assembly cavity, and then placed in the high temperature and high pressure synthesis equipment. The pressure is set to 10 GPa and the temperature is 1000 ℃. The temperature and pressure are maintained for 5 min to obtain the magnetic diamond composite material.

[0038] Example 7 A method for preparing a magnetic diamond composite material, referenced Figures 1-2 This includes the following steps: (1) Weigh 1 g of iron oxide and nano-graphite powder at a mass ratio of 1:9, add anhydrous ethanol, and grind thoroughly for 30 min using an agate mortar to obtain a high-temperature and high-pressure synthesis precursor material; wherein the particle size of iron oxide is 20 nm and the particle size of nano-graphite powder is 600 nm. (2) The high-temperature and high-pressure synthesis precursor material obtained in step (1) is dried in a vacuum atmosphere at 100 °C; (3) The precursor material dried in step (2) is filled into the high temperature and high pressure synthesis assembly cavity, and then placed in the high temperature and high pressure synthesis equipment. The pressure is set to 20 GPa and the temperature is 1000 ℃. The temperature and pressure are maintained for 15 min to obtain the magnetic diamond composite material.

[0039] Example 8 A method for preparing a magnetic diamond composite material, referenced Figures 1-2 This includes the following steps: (1) Weigh 1 g of iron oxide and nano-graphite powder in a mass ratio of 9:999, add anhydrous ethanol, and grind thoroughly for 30 min using an agate mortar to obtain a high-temperature and high-pressure synthesis precursor material; wherein the particle size of iron oxide is 20 nm and the particle size of nano-graphite powder is 600 nm. (2) The high-temperature and high-pressure synthesis precursor material obtained in step (1) is dried in a vacuum atmosphere at 100 °C; (3) The precursor material dried in step (2) is filled into the high temperature and high pressure synthesis assembly cavity, and then placed in the high temperature and high pressure synthesis equipment. The pressure is set to 13 GPa and the temperature is 1500 ℃. The temperature and pressure are maintained for 15 min to obtain the magnetic diamond composite material.

[0040] Example 9 A method for preparing a magnetic diamond composite material, referenced Figures 1-2 This includes the following steps: (1) Weigh 1 g of iron oxide and nano-graphite powder at a mass ratio of 5:499, add anhydrous ethanol, and grind thoroughly for 30 min using an agate mortar to obtain a high-temperature and high-pressure synthesis precursor material; wherein the particle size of iron oxide is 20 nm and the particle size of nano-graphite powder is 600 nm. (2) The high-temperature and high-pressure synthesis precursor material obtained in step (1) is dried in a vacuum atmosphere at 100 °C; (3) The precursor material dried in step (2) is filled into the high temperature and high pressure synthesis assembly cavity, and then placed in the high temperature and high pressure synthesis equipment. The pressure is set to 13 GPa and the temperature is 1500 ℃. The temperature and pressure are maintained for 15 min to obtain the magnetic diamond composite material.

[0041] Example 10 A method for preparing a magnetic diamond composite material, referenced Figures 1-2 This includes the following steps: (1) Weigh 1 g of iron oxide and nano-graphite powder at a mass ratio of 3:299, add anhydrous ethanol, and grind thoroughly for 30 min using an agate mortar to obtain a high-temperature and high-pressure synthesis precursor material; wherein the particle size of iron oxide is 20 nm and the particle size of nano-graphite powder is 600 nm. (2) The high-temperature and high-pressure synthesis precursor material obtained in step (1) is dried in a vacuum atmosphere at 100 °C; (3) The precursor material dried in step (2) is filled into the high temperature and high pressure synthesis assembly cavity, and then placed in the high temperature and high pressure synthesis equipment. The pressure is set to 13 GPa and the temperature is 1500 ℃. The temperature and pressure are maintained for 15 min to obtain the magnetic diamond composite material.

[0042] Since all of Examples 1-10 prepared magnetic diamond composite materials with the expected effects of the present invention, the following description will only take the magnetic diamond composite material prepared in Example 1 as an example to illustrate its effects and performance.

[0043] Figures 1-5 The results are from characterization tests performed on the magnetic diamond composite material synthesized in Example 1.

[0044] Figure 1 An optical image of a polished cross-section of a magnetic diamond composite material; Figure 2 Optical image of the polished side of a magnetic diamond composite material; Figure 3 This is a scanning electron microscope image of a magnetic diamond composite material after synthesis and polishing. Figure 1 and Figure 2 It can be clearly observed that the macroscopic structure of this magnetic composite diamond material is dense and regular, with a high degree of integrity in its cross-section and sides. There are no obvious defects such as cracks, pores, delamination, or interface peeling. The morphology of each region is uniform and stable, fully demonstrating the integrity of the structure. Figure 3 This allows for further observation of the microstructure characteristics of the composite material. The magnetic particles are uniformly dispersed in the diamond matrix, with no agglomeration or segregation. The particle size distribution is uniform and the morphology is regular. The interface between the particles and the diamond matrix is ​​tightly bonded, with no obvious gaps or microcracks. The two form a continuous and stable microstructure, providing reliable microstructure support for the composite material to possess both superhard mechanical and magnetic properties.

[0045] Figure 4 The images show Vickers hardness test results of the synthesized magnetic diamond composite material. The hardness of the synthesized sample was characterized at room temperature using a KB30S hardness tester, with a 1 kg load applied to a diamond pyramidal indenter. Figure 4 It can be clearly observed that after the hardness test, the indentation outline on the material surface is clear and regular, with no obvious chipping or peeling at the indentation edges, and no microcracks extending outward from the indentation, fully demonstrating the excellent deformation resistance and structural density of the composite material. According to the test results, the HV1 of this material is 4128, clearly indicating that the Vickers hardness of this material exceeds 40 GPa, belonging to the category of superhard materials.

[0046] Figure 5The results show the magnetic properties of the synthesized magnetic diamond composite material. Magnetization was measured using a Physical Property Measurement System (PPMS, EverCool II, Quantum Design, USA), equipped with a Vibrating Sample Magnetometer (VSM) accessory. The magnetic field strength measurement range was -10000 Oe to 10000 Oe. Figure 5 As can be seen, the hysteresis loop of the material is smooth and uniform, proving that the magnetic properties of the composite material originate from a single source and are not affected by the magnetic properties of other impurity phases. Test data shows that the saturation magnetization of this composite material is 0.5 emu / g and the remanence is 0.2 emu / g, exhibiting tunable magnetic properties.

[0047] The characterization results above demonstrate that the magnetic diamond composite material synthesized under high temperature and pressure exhibits a dense and complete macroscopic structure, free from cracks and voids; at the microscopic level, magnetic particles are uniformly dispersed within the matrix. Its Vickers hardness exceeds 40 GPa, placing it within the category of superhard materials; the hysteresis loop is smooth and uniform, with a single source of magnetism, achieving a synergistic combination of mechanical and magnetic properties.

[0048] Comparative Example 1 The only difference from Example 1 is that: The precursor material was high-purity graphite powder. The synthesis was carried out at a pressure of 5 GPa, a temperature of 1500 ℃, and a holding time of 60 min.

[0049] The temperature and pressure conditions at this point did not meet the critical thermodynamic conditions for the graphite-diamond phase transformation. High-purity graphite powder was difficult to convert into diamond, and the product was mainly the untransformed graphite phase, preventing the formation of a diamond matrix superhard structure. The hardness of the synthesized sample was characterized at room temperature using a KB30S hardness tester. When a 1 kg load was applied to the diamond pyramidal indenter, the sample underwent structural collapse under the standard Vickers hardness tester load, resulting in an inability to obtain an effective hardness value. This indicated excessively low hardness and a loose structure, failing to meet the Vickers hardness standard of 40 GPa for superhard materials.

[0050] Meanwhile, to evaluate the strength of the matrix and the bonding force between particles, a fixed abrasive grinding experiment was conducted on the samples using 600-grit silicon carbide sandpaper. The results showed that due to the low hardness of the graphite matrix, it could not provide effective mechanical support for the magnetic particles. Under the action of grinding shear stress, the matrix underwent severe plastic deformation and removal, leading to large-area peeling and detachment of magnetic particles. This confirms that under current temperature and pressure conditions, the graphite matrix failed to form a diamond framework with high wear resistance, resulting in insufficient strength and preventing the graphite matrix from stably encapsulating magnetic particles.

[0051] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0052] The specification of this application provides examples of various optional materials for the components. However, those skilled in the art should understand that the above list of components is not restrictive or exhaustive. Various components can be replaced by other equivalent materials not mentioned in the specification of this application, and the purpose of this application can still be achieved.

[0053] Furthermore, the dosage range of each component in this application includes any combination of the lower and upper limits mentioned in the specification. All these ranges are covered within the scope of this application; however, for the sake of brevity, these combined ranges are not listed one by one in the specification. Each feature of this application listed in the specification can be combined with any other feature of the application, and such combinations are also within the scope of disclosure of this application. However, for the sake of brevity, these combined ranges are not listed one by one in the specification.

Claims

1. A method for preparing a magnetic diamond composite material, characterized in that, Includes the following steps: The magnetic particle material is ground and mixed with the diamond superhard matrix material, and then dried to obtain the precursor material. The precursor material was treated at 5 GPa~20 GPa and 1000℃~2000℃ for 5 min~120 min, and the resulting product was then surface polished to obtain the magnetic diamond composite material.

2. The preparation method according to claim 1, characterized in that, The processing conditions for the precursor are: 12 GPa~20 GPa, 1000℃~2000℃ for 5 min~120 min.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the magnetic particle material to the diamond superhard matrix material is 1~9:1~999.

4. The preparation method according to claim 1, characterized in that, The magnetic particle material includes at least one ferrite soft magnetic material.

5. The preparation method according to claim 4, characterized in that, The magnetic particle material is selected from one or a combination of several of magnesium ferrite, zinc ferrite, manganese ferrite, nickel ferrite, and iron(III) oxide; the size of the magnetic particle material is 5 nm to 50 μm.

6. The preparation method according to claim 1, characterized in that, The diamond superhard matrix material is selected from diamond phase materials or graphite phase materials.

7. The preparation method according to claim 6, characterized in that, The diamond phase material is selected from any one of nano diamond powder, micron diamond powder, nanotwinned diamond, and porous diamond; the graphite phase material is selected from any one of flake graphite, nano graphite powder, single-walled carbon nanotubes, multi-walled carbon nanotubes, fullerene, graphene, glassy carbon, and amorphous carbon; the size of the diamond phase material is 5 nm to 1000 nm, and the size of the graphite phase material is 5 nm to 1000 nm.

8. A magnetic diamond composite material prepared according to any one of claims 1 to 7, characterized in that, The magnetic diamond composite material is magnetic and has a Vickers hardness greater than 40 GPa.

9. The application of the magnetic diamond composite material according to claim 8 in energy and power, electronic information, high-end manufacturing, new energy, biomedicine, aerospace, and national defense industries.

10. The application according to claim 9, characterized in that, The magnetic diamond composite material is used to prepare core components of magnetic sensors, magnetic core materials for high-temperature and high-frequency electronic devices, magnetoelectric conversion components for new energy equipment, or anti-interference magnetic shielding components for military and special equipment.

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