A method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering

Abstract

This invention belongs to the field of ceramic materials technology and discloses a method for preparing high-entropy oxide-silicon carbide composite ceramics by hot-pressing sintering. High-entropy oxide precursor powder and silicon carbide powder are used as raw materials, and a mixed powder is obtained by wet ball milling or dry ball milling. The mixed powder is placed in a graphite mold in a hot-pressing sintering furnace, pressure is applied, and hot-pressing sintering is carried out at 1200–1500℃ under a vacuum or argon protective atmosphere. After heat treatment, high-entropy oxide-silicon carbide composite ceramics are synthesized through in-situ reaction. This invention optimizes the hot-pressing sintering process. The high-entropy effect provides a stable matrix and a compatible interface; the activity of high-entropy oxide promotes densification; SiC, as a hard reinforcing phase, enhances the strength and toughness of the composite material through particle strengthening and crack deflection mechanisms; the thermally conductive network constructed by SiC combines the high wear resistance and excellent heat dissipation capacity of high-entropy oxide, solving the inherent contradiction of its wear resistance but not heat resistance, and achieving a breakthrough in comprehensive performance.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, specifically relating to a method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering. Background Technology

[0002] With the rapid development of science and technology and modern industry in my country, the economic losses caused by energy and material consumption due to material wear are quite staggering. Currently, wear-resistant materials are mainly classified into three categories: metals, ceramics, and ceramic / metal composites. Due to the low melting point of metal materials, they are prone to softening and deformation during friction. Although ceramic / metal composites have excellent wear resistance, their composite layer thickness is often too small, making them susceptible to casting defects. Therefore, in recent years, research on wear-resistant materials has focused on ceramic materials with excellent thermal stability and mechanical properties.

[0003] High-entropy ceramics are a new type of ceramic material developed in recent years, attracting widespread attention and research due to their unique structure and performance characteristics. Compared with single-component ceramics, high-entropy ceramics exhibit higher thermal stability and mechanical properties. The components of high-entropy ceramics tend to be arranged randomly, resulting in a disordered chemical composition and thus different properties from traditional doped ceramics. Due to their multiple principal components, they exhibit a "collective characteristic." Since their inception, high-entropy ceramics have demonstrated unique properties, such as excellent wear and heat resistance, and extremely high hardness, due to the greater freedom in composition design and performance control.

[0004] Oxide ceramics possess high thermal stability, strong oxidation resistance, and low cost. Their wear resistance can be improved through high-entropy sintering, representing a revolutionary breakthrough in the field of wear-resistant ceramics. However, high-entropy oxides have low thermal conductivity, and under harsh environments, intense frictional heat can easily lead to material softening at high temperatures, reducing wear resistance and shortening service life. Therefore, developing a technology for hot-pressing sintering to prepare high-entropy oxide-silicon carbide composite ceramics is of significant practical importance for promoting the development of composite ceramic materials. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for preparing high-entropy oxide-silicon carbide composite ceramics via hot-pressing sintering. The synergistic effect of in-situ synthesis of the high-entropy oxide and its composite with SiC ceramics significantly improves the thermal conductivity of the composite material while maintaining the excellent mechanical properties of the high-entropy oxide. Hot-pressing sintering is employed to achieve in-situ synthesis of the high-entropy phase under high temperature and pressure. This in-situ synthesis of the high-entropy phase, combined with silicon carbide ceramics, achieves dense sintering, resulting in a composite ceramic material with high hardness, high strength, and excellent performance. Through precise control of the hot-pressing sintering process parameters, the optimized combination of the two materials in the microstructure is achieved, yielding a dense, uniform, and high-performance composite ceramic material.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering, comprising the following steps:

[0007] Step 1: Preparation of sintering precursor mixed powder: Using high-entropy oxide precursor powder and silicon carbide powder as raw materials, ball milling is used. The ball-milled powder is then dried at 80℃ for 12 hours to obtain the mixed powder.

[0008] Among them, high-entropy oxide precursor powder includes Five or seven oxides of NiO and CuO are added, and the amount of silicon carbide powder accounts for 10-50% of the total weight of the raw materials. When the SiC content is <10%, the thermal conductivity improvement effect is limited. When the SiC content is >50%, the high-entropy oxide bonding phase is insufficient, which affects the densification and mechanical properties of the composite ceramic material.

[0009] Step 2: Hot pressing sintering of mixed powder: The mixed powder is placed in a graphite mold in a hot pressing sintering furnace. The inner wall of the graphite mold is coated with BN release agent. Hot pressing sintering is carried out under vacuum or argon protective atmosphere. The sintering temperature is 1200-1500℃, the heating rate is 5-20℃ / min, the pressure applied to the graphite mold is 5-60MPa, and the holding time is 0.5-10h.

[0010] Step 3: After sintering, cool the furnace to room temperature, controlling the cooling rate to ≤10℃ / min, to obtain high-entropy oxide-silicon carbide composite ceramic material;

[0011] The hardness of high-entropy oxide-silicon carbide composite ceramics is ≥18GPa and the thermal conductivity is ≥25W / (m·K).

[0012] in, The purity is 99.99% and the particle size is 80nm.

[0013] in, The purity is 99%, and the particle size is 50-80 nm.

[0014] The NiO has a purity of 99.5% and a particle size of 30 nm.

[0015] in, The purity is 99.8%, and the particle size is 5-10 nm.

[0016] The CuO has a purity of 99.9% and a particle size of 50 nm.

[0017] in, The purity is 99.9% and the particle size is 80nm.

[0018] in, The purity is 99.95% and the particle size is 80nm.

[0019] The particle size of SiC powder is 500 nm to 10 μm.

[0020] The The five oxides were mixed in a molar ratio of 1:1:2:1~2:1~2.

[0021] The CuO is prepared by mixing seven oxides in a molar ratio of 1 to 5:1:1:1:1:1:1.

[0022] In step one, dry or wet ball milling is used. The ball milling parameters are: ball-to-material ratio of 2:1 to 10:1, rotation speed of 200 to 500 rpm, and time of 6 to 24 hours. The wet ball milling media are anhydrous ethanol, acetone, or isopropanol. The weight ratio of ball milling media to raw material is 0.5 to 1.5:1.

[0023] When the sintering atmosphere in step two is a vacuum atmosphere, the vacuum level is... When the sintering atmosphere is an argon protective atmosphere, the purity of the high-purity argon gas is ≥99.99%.

[0024] In step two, pressure is applied in stages during sintering. In the initial stage of heating, a low pressure of 5-25 MPa is applied to promote particle rearrangement, and in the later stage of heating, a high pressure of 45-60 MPa is applied to promote densification.

[0025] The high-entropy oxide-silicon carbide composite ceramic is used in high-temperature wear-resistant parts or thermal management materials.

[0026] This invention uses raw materials comprising at least five oxides, which react in situ at high temperatures to synthesize a high-entropy phase. Silicon carbide has extremely strong covalent bonds. It relies on the high-entropy phase generated to bind (bond) silicon carbide. The resulting high-entropy oxide-silicon carbide composite ceramic combines the unique mechanical properties of high-entropy oxide ceramics with the high thermal conductivity of silicon carbide ceramics. The prepared composite ceramic material has excellent properties such as high hardness and high strength.

[0027] The performance advantages of the high-entropy oxide-silicon carbide (SiC) composite ceramic of this invention stem from the multiple synergistic effects of the two in thermodynamics, sintering kinetics, microstructure, and performance. When five or more metallic elements coexist in approximately equal proportions in the same crystal lattice, the configurational entropy of the entire system becomes extremely high. This extremely high degree of disorder plays a stabilizing role thermodynamically, causing the material to tend to form a single, stable solid solution phase at high temperatures, rather than separating into multiple simple oxides. The high-entropy oxide matrix itself has a stable phase structure at sintering and service temperatures and is not easily decomposed; its core lies in "high-entropy stabilization." By carefully selecting the element combination, the chemical properties of the high-entropy oxide can be adjusted so that it is not thermodynamically prone to violent chemical reactions (such as the formation of excessive low-melting-point silicates) when in contact with SiC at high temperatures. The two usually form a friendly interface, mainly through physical bonding and limited interdiffusion of elements, avoiding the formation of a harmful brittle reaction layer.

[0028] This invention employs an in-situ reaction mechanism and hot-pressing sintering. The coexistence of multiple elements lowers the eutectic point of the system. In the range of 1000–1300℃, multiple oxides form a high-entropy oxide solid solution through solid-phase diffusion. This allows the high-entropy oxides to generate a small amount of liquid phase or exhibit extremely high solid-state diffusion activity at relatively low temperatures (e.g., 1200–1400℃). These formed active substances can wet and encapsulate high-strength SiC particles, drawing the particles closer together through capillary forces. Through a dissolution-precipitation mechanism, material transport and pore filling are achieved. High pressure promotes pore closure and grain boundary migration, thereby significantly promoting the densification of the entire composite, achieving near-complete densification (relative density ≥98%).

[0029] The composite of high-entropy oxides and SiC can mutually promote and synergistically densify, resulting in superior performance. This solves the problem of the difficulty in sintering pure SiC due to its extremely strong covalent bonds. After synergistic sintering, the composite material forms a unique two-phase microstructure; SiC particles, as the reinforcing phase, are uniformly embedded in the high-entropy oxide matrix. The interface between the two is clear and clean, typically consisting of only a nanoscale interdiffusion layer, without a thick, brittle reaction layer. This structure brings about a strengthening effect in the particle-reinforced composite material. The hard SiC particles directly bear external loads, resisting plastic deformation and wear; the high-entropy oxide matrix acts as a bond and transfers loads, while its own solid solution strengthening and grain refinement also enhance the material's hardness.

[0030] Through the synergistic integration of advantages, the mechanical properties of high-entropy oxide-SiC composite ceramic materials are synergistically enhanced, exhibiting strengthening and toughening effects. This is attributed to the dispersion strengthening of hard SiC particles, the solid solution strengthening of the high-entropy oxide matrix, and the fine grain size. When cracks propagate within the material, they encounter SiC particles. Unable to easily penetrate the harder SiC, the cracks are deflected, bypassing the particles or propagating along the interface. This process significantly prolongs the crack propagation path, consuming more energy and thus improving the material's fracture toughness. Furthermore, due to the difference in thermal expansion coefficients between the two materials, moderate residual stress is generated near the interface after cooling, which also helps to hinder crack propagation.

[0031] The composite ceramic material of this invention possesses excellent thermal and tribological properties. Oxide ceramics are inherently poor conductors of heat, exhibiting extremely high thermal resistance. During service, particularly during wear, they generate exceptionally high amounts of heat. The unavoidable release of this heat can lead to localized overheating, causing the oxide ceramic to soften and affecting its usability. SiC, on the other hand, possesses inherently high thermal conductivity. When its content in the matrix is ​​sufficient and its distribution is uniform, it can interconnect to form a rapidly conducting network or pathway. This is analogous to embedding metal wires in thermal insulation materials to construct heat conduction pathways. Adding silicon carbide to oxide ceramics allows for rapid conduction of localized high temperatures, preventing softening due to excessive localized temperatures and thus extending the service life of the composite ceramic.

[0032] Furthermore, during friction and wear, a large amount of heat is generated at the contact surface. Traditional high-entropy oxides, due to their poor thermal conductivity, experience heat accumulation leading to surface softening and accelerated wear. However, in this composite material, the generated frictional heat can be rapidly dissipated from the surface to the interior and overall structure of the material through the thermally conductive network constructed by SiC, preventing a sharp increase in local temperature. This composite material also possesses an adaptive wear-resistant surface. During friction, the surface material undergoes slight oxidation and plastic flow, forming an extremely thin, dense, and tough enamel layer. This in-situ formed protective layer further reduces the wear rate. Thus, the surface material's hardness and wear resistance are maintained, significantly extending its service life.

[0033] The beneficial effects of this invention are as follows: This invention synthesizes high-entropy oxide-silicon carbide composite ceramics through hot pressing sintering and in-situ reaction. The preparation of high-entropy oxide-silicon carbide composite ceramics is a multi-level synergistic process. The high-entropy effect provides a stable matrix and a compatible interface. During sintering, the activity of high-entropy oxides promotes densification. In the final microstructure, SiC, as a hard reinforcing phase, enhances the strength and toughness of the composite material through particle strengthening and crack deflection mechanisms. The thermally conductive network constructed by SiC combines the high wear resistance and excellent heat dissipation capacity of high-entropy oxides, solving the inherent contradiction of wear resistance but not heat resistance, achieving a breakthrough in comprehensive performance, and providing a feasible technical path for designing high-performance wear-resistant and heat-resistant structural ceramics. Attached Figure Description

[0034] Figure 1 The XRD pattern of the high-entropy oxide-SiC composite ceramic prepared in Example 1 of this invention;

[0035] Figure 2 The image shows the microstructure of the high-entropy oxide-SiC composite ceramic prepared in Example 1 of this invention.

[0036] Figure 3 The microstructure of the high-entropy oxide-SiC composite ceramic prepared in Example 1 of this invention is shown in the EDS energy spectrum.

[0037] Figure 4 The image shows the microstructure of the high-entropy oxide-SiC composite ceramic prepared in Example 2 of this invention.

[0038] Figure 5 The image shows the microstructure of the high-entropy oxide-SiC composite ceramic prepared in Example 3 of this invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0040] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; and the reagents and materials used are commercially available unless otherwise specified.

[0041] Example 1

[0042] A method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering includes the following steps:

[0043] Step 1: Preparation of sintering precursor mixed powder: Using high-entropy oxide precursor powder and silicon carbide powder as raw materials, the high-entropy oxide precursor powder includes... Five oxides were mixed in a molar ratio of 1:1:2:2:1, with silicon carbide powder accounting for 25% of the total weight of the raw materials. Wet ball milling was performed using isopropanol as the medium, with an isopropanol-to-raw material weight ratio of 0.5:1. The ball milling parameters were a ball-to-material ratio of 2:1, a rotation speed of 200 rpm, and a time of 12 hours. The ball-milled mixed powder was then dried at 80℃ for 12 hours to obtain the final mixed powder.

[0044] Step 2: Hot pressing and sintering of the mixed powder: The mixed powder is placed in a graphite mold in a hot pressing furnace. The inner wall of the graphite mold is coated with BN release agent to prevent adhesion. Hot pressing and sintering is carried out under an argon protective atmosphere with a purity ≥99.99%. The sintering temperature is 1200℃, and the heating rate is 5℃ / min. Pressure is applied to the graphite mold in stages: a low pressure of 20-25MPa is applied in the initial 1 / 3 heating stage, a pressure of 35-40MPa is applied in the middle heating stage, and a high pressure of 55-60MPa is applied in the final 1 / 3 heating stage. The holding time is 0.5h, and the pressure during the holding stage is 35-40MPa.

[0045] Step 3: After sintering, cool the furnace to room temperature, controlling the cooling rate to ≤10℃ / min, to obtain high-entropy oxide-silicon carbide composite ceramic material.

[0046] Example 2

[0047] A method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering includes the following steps:

[0048] Step 1: Preparation of sintering precursor mixed powder: Using high-entropy oxide precursor powder and silicon carbide powder as raw materials, the high-entropy oxide precursor powder includes... Seven oxides, including NiO and CuO, were mixed in a molar ratio of 1:1:1:1:1:1:1, with silicon carbide powder accounting for 50% of the total raw material weight. Wet ball milling was performed using anhydrous ethanol as the medium, with an anhydrous ethanol to raw material weight ratio of 1.5:1. The ball milling parameters were: ball-to-material ratio 8:1, rotation speed 350 rpm, and time 24 h. The ball-milled mixture was then dried at 80℃ for 12 h to obtain the final powder.

[0049] Step 2: Hot pressing and sintering of the mixed powder: The mixed powder is placed in a graphite mold in a hot pressing furnace. The inner wall of the graphite mold is coated with BN release agent to prevent adhesion. Hot pressing and sintering is carried out under an argon protective atmosphere with a purity of ≥99.999%. The sintering temperature is 1350℃, and the sintering heating rate is 15℃ / min. Pressure is applied to the graphite mold in a segmented pressurization manner. The initial 1 / 3 heating stage is subjected to a low pressure of 15-20MPa, the middle heating stage is subjected to a pressure of 35-40MPa, and the final 1 / 3 heating stage is subjected to a high pressure of 50-55MPa. The holding time is 6 hours, and the pressure during the holding stage is 40-45MPa.

[0050] Step 3: After sintering, cool the furnace to room temperature, controlling the cooling rate to ≤10℃ / min, to obtain high-entropy oxide-silicon carbide composite ceramic material.

[0051] Example 3

[0052] A method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering includes the following steps:

[0053] Step 1: Preparation of sintering precursor mixed powder: Using high-entropy oxide precursor powder and silicon carbide powder as raw materials, the high-entropy oxide precursor powder includes... Seven CuO oxides were mixed in a molar ratio of 5:1:1:1:1:1:1:1; silicon carbide powder accounted for 40% of the total weight of the raw materials; dry ball milling was used with ball-to-material ratio of 10:1, rotation speed of 500 rpm, and time of 12 hours to obtain the mixed powder.

[0054] Step 2: Hot pressing and sintering of the mixed powder: The mixed powder is placed in a graphite mold in a hot pressing furnace. The inner wall of the graphite mold is coated with BN release agent to prevent adhesion. Under vacuum conditions... Hot pressing sintering is carried out under protective conditions; the sintering temperature is 1500℃, the heating rate is 20℃ / min, and pressure is applied to the graphite mold in a segmented pressurization manner. The initial 1 / 3 heating stage is subjected to low pressure of 5-10MPa, the middle heating stage is subjected to pressure of 20-30MPa, and the final 1 / 3 heating stage is subjected to high pressure of 45-50MPa; the holding time is 10h, and the holding stage is subjected to pressure of 30-35MPa.

[0055] Step 3: After sintering, cool the furnace to room temperature, controlling the cooling rate to ≤10℃ / min, to obtain high-entropy oxide-silicon carbide composite ceramic material.

[0056] Example 4

[0057] A method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering includes the following steps:

[0058] Step 1: Preparation of sintering precursor mixed powder: Using high-entropy oxide precursor powder and silicon carbide powder as raw materials, the high-entropy oxide precursor powder includes... Seven oxides, including NiO and CuO, were mixed in a molar ratio of 3:1:1:1:1:1:1:1, with silicon carbide powder accounting for 20% of the total raw material weight. A wet ball milling process was used, with acetone as the medium and an acetone-to-raw material weight ratio of 1:1. The ball milling parameters were a ball-to-material ratio of 6:1, a rotation speed of 400 rpm, and a time of 18 hours. The ball-milled mixture was then dried at 80℃ for 12 hours to obtain the final powder.

[0059] Step 2: Hot pressing and sintering of the mixed powder: The mixed powder is placed in a graphite mold in a hot pressing furnace. The inner wall of the graphite mold is coated with BN release agent to prevent adhesion. Hot pressing and sintering is carried out under an argon protective atmosphere with a purity of ≥99.99%. The sintering temperature is 1400℃, and the sintering heating rate is 10℃ / min. Pressure is applied to the graphite mold in a segmented pressurization manner. The initial 1 / 3 heating stage is subjected to a low pressure of 15-20MPa, the middle heating stage is subjected to a pressure of 35-40MPa, and the final 1 / 3 heating stage is subjected to a high pressure of 55-60MPa. The holding time is 6 hours, and the pressure during the holding stage is 45-50MPa.

[0060] Step 3: After sintering, cool the furnace to room temperature, controlling the cooling rate to ≤10℃ / min, to obtain high-entropy oxide-silicon carbide composite ceramic material.

[0061] Example 5

[0062] A method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering includes the following steps:

[0063] Step 1: Preparation of sintering precursor mixed powder: Using high-entropy oxide precursor powder and silicon carbide powder as raw materials, the high-entropy oxide precursor powder includes... Five oxides were mixed in a molar ratio of 1:1:2:1:2, with silicon carbide powder accounting for 40% of the total weight of the raw materials. Wet ball milling was performed using anhydrous ethanol as the medium, with an anhydrous ethanol to raw material weight ratio of 1.5:1. The ball milling parameters were a ball-to-material ratio of 5:1, a rotation speed of 300 rpm, and a time of 6 hours. The ball-milled mixed powder was then dried at 80℃ for 12 hours to obtain the final mixed powder.

[0064] Step 2: Hot pressing and sintering of the mixed powder: The mixed powder is placed in a graphite mold in a hot pressing furnace. The inner wall of the graphite mold is coated with BN release agent to prevent adhesion. Under vacuum conditions... Hot pressing sintering is carried out under protective conditions; the sintering temperature is 1300℃, and the heating rate is 10℃ / min; pressure is applied to the graphite mold in a segmented pressurization manner, with low pressure of 15-20MPa applied in the initial heating stage, pressure of 35-40MPa applied in the middle heating stage, and high pressure of 45-50MPa applied in the later heating stage; the holding time is 4.5h, and the pressure applied in the holding stage is 40-45MPa;

[0065] Step 3: After sintering, cool the furnace to room temperature, controlling the cooling rate to ≤10℃ / min, to obtain high-entropy oxide-silicon carbide composite ceramic material.

[0066] The composite ceramic materials prepared in Examples 1-5 were subjected to performance tests, and the test results are shown in the table below:

[0067]

[0068] The above embodiments are merely examples illustrating the explanation, specific implementation, and effects of the present invention, and are not intended to limit the invention. Based on this disclosure, some modifications or improvements without contributing any inventive step can be made, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of this disclosure fall within the scope of protection claimed in this disclosure.

Claims

1. A method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering, characterized in that, Includes the following steps: Step 1: Preparation of sintering precursor mixed powder: Using high-entropy oxide precursor powder and silicon carbide powder as raw materials, ball milling and drying are used to obtain mixed powder; The high-entropy oxide precursor powder is prepared by mixing five oxides, Al2O3, Y2O3, ZrO2, CeO2, and TiO2, in a molar ratio of 1:1:2:1 to 2:1 to 2, or by mixing seven oxides, Al2O3, NiO, Y2O3, ZrO2, CeO2, TiO2, and CuO, in a molar ratio of 1 to 5:1:1:1:1:1:

1. The amount of silicon carbide powder added accounts for 10% to 50% of the total weight of the raw materials. Step 2: Hot pressing sintering of mixed powder: The mixed powder is placed in a graphite mold in a hot pressing sintering furnace. The inner wall of the graphite mold is coated with BN release agent. Hot pressing sintering is carried out under vacuum or argon protective atmosphere. The sintering temperature is 1200-1500℃, the heating rate is 5-20℃ / min, the pressure applied to the graphite mold is 5-60MPa, and the holding time is 0.5-10h. Step 3: After sintering, cool the furnace to room temperature, controlling the cooling rate to ≤10℃ / min, to obtain high-entropy oxide-silicon carbide composite ceramic material; The hardness of high-entropy oxide-silicon carbide composite ceramics is ≥18GPa and the thermal conductivity is ≥25W / (m·K).

2. The method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering according to claim 1, characterized in that: The purity of Al2O3 is 99.99% and the particle size is 80nm; the purity of ZrO2 is 99% and the particle size is 50-80nm; the purity of NiO is 99.5% and the particle size is 30nm.

3. The method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering according to claim 1, characterized in that: TiO2 has a purity of 99.8% and a particle size of 5–10 nm; CuO has a purity of 99.9% and a particle size of 50 nm; Y2O3 has a purity of 99.9% and a particle size of 80 nm; CeO2 has a purity of 99.95% and a particle size of 80 nm.

4. The method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering according to claim 1, characterized in that: The particle size of SiC powder is 500 nm to 10 μm.

5. The method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering according to claim 1, characterized in that: In step one, dry or wet ball milling is used. The ball milling parameters are a ball-to-material ratio of 2:1 to 10:1, a rotation speed of 200 to 500 rpm, and a time of 6 to 24 hours. The wet ball milling media are anhydrous ethanol, acetone, or isopropanol, and the weight ratio of the ball milling media to the raw material is 0.5 to 1.5:

1.

6. The method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering according to claim 1, characterized in that: In step one, the ball-milled powder is dried at a temperature of 80°C for 12 hours.

7. The method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering according to claim 1, characterized in that: When the sintering atmosphere in step two is a vacuum atmosphere, the vacuum degree is ≤10. -2 Pa; when the sintering atmosphere is an argon protective atmosphere, the purity of the high-purity argon gas is ≥99.99%.

8. The method for preparing high-entropy oxide-silicon carbide composite ceramics by hot pressing sintering according to claim 1, characterized in that: In step two, pressure is applied in stages during sintering. Low pressure of 5-25 MPa is applied in the initial stage of heating, and high pressure of 45-60 MPa is applied in the later stage of heating.

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