High-entropy carbide ceramic as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of carbide ceramics, and particularly relates to a high-entropy carbide ceramic as well as a preparation method and application thereof. The compact single-phase high-entropy carbide ceramic with excellent high-temperature friction performance is developed by aiming at the problems that the high-temperature friction performance of the existing high-entropy carbide ceramic is insufficient to research and the wear resistance is relatively poor, and the component of the compact single-phase high-entropy carbide ceramic is (Ti0. 2Zr0. 2Nb0. 2Mo0. 2W0. 2) C. The invention further discloses a preparation method of the compact single-phase high-entropy carbide ceramic. According to the material, by optimizing the component design, the defects of friction coefficient fluctuation and high wear rate of traditional high-entropy carbide in a high-temperature environment are overcome. Through a specific sintering process, a compact single-phase structure is realized, and the high-temperature friction stability and wear resistance are remarkably improved. The material is suitable for aerospace engine hot end parts, turbine sealing rings, brake friction plates and other extreme working condition scenes, and can meet the requirements of high-speed scraping, high-temperature sealing and long service life.

Description

Technical Field

[0001] The invention relates to a high-entropy carbide ceramic and a preparation method and application thereof, belonging to the field of high-entropy ceramics. Background Art

[0002] The concept of high-entropy materials was first proposed by Ye Junwei in 2004. The original high-entropy materials were high-entropy alloys (HEAs), also known as multi-component alloys. Compared with traditional alloys, the components of high-entropy alloys tend to form single-phase solid solutions, which gives them four unique properties: high-entropy effect, hysteresis diffusion effect, lattice distortion effect and "cocktail" effect. The concept of high-entropy ceramics originated from high-entropy alloys. According to their chemical composition, they can be divided into high-entropy carbides, high-entropy oxides, high-entropy nitrides and high-entropy borides. Among them, high-entropy carbide ceramics exhibit higher hardness, better wear resistance, lower thermal conductivity and more excellent corrosion resistance than single-component ceramics. Their performance far exceeds that of conventional metals and most engineering ceramics, and they perform excellently in many extreme environments. It can be used in hot-end components of aerospace engines, such as turbine engine sealing rings and blade tips, friction plates of aviation brake systems, bearings in transmission devices of heat treatment furnaces in steel plants, turbine blade tenons and turbine disc sealing rings of heavy-duty gas turbines, high-temperature nozzles of laser cutting equipment, etc. These parts require the material to maintain stable friction with the wear parts, while at the same time being able to withstand high-speed scraping, provide effective sealing and ensure service life.

[0003] Reference 1 (J. Adv. Ceram. 12 (2023) 242-257) reported that a mixed powder of TiC, V8C7, NbC, Mo2C and WC was milled in ethanol with tungsten carbide balls for 8 h and then spark plasma sintered to prepare (TiVNbMoW)C 4.375 Methods for bulk high-entropy ultrahigh-temperature ceramic materials. (TiVNbMoW)C 4.375 High entropy carbide ceramics exhibit low friction coefficient at room temperature and 800 ℃. Al2O3 is used as the friction material, (TiVNbMoW)C 4.375 The average friction coefficient at room temperature is 0.49, the friction coefficients at 400℃ and 800℃ are 0.7 and 0.54 respectively, and the wear rates are 2.6×10 -6 , 2.5×10 -5 , 3.4×10 -4 .

[0004] Reference 2 (Tribol. Int. 157 (2021) 106883) reports a method for preparing (HfMoNbTaTi)C bulk high-entropy ceramics using a planetary ball mill to mix a mixed powder of HfO2, MoO3, Nb2O5, Ta2O5, TiO2, and graphite in ethanol. The powders were then uniformly mixed using a planetary ball mill and then spark plasma sintering (1800°C, 15 MPa, and a holding time of 20 min). The (HfMoNbTaTi)C high-entropy carbide ceramics, using Al2O3 as the counter-friction material, exhibited friction coefficients of approximately 0.6, 1.1, 0.8, and 0.7 at room temperature, 300°C, 600°C, and 900°C, respectively, and wear rates of 3.11×10 -7 , 6.86×10 -7 , 1.21×10 -5 and 1×10 -4 .

[0005] However, the friction properties of existing high-entropy carbide ceramic materials at high temperatures have been little studied and their wear resistance is poor. There is an urgent need to prepare high-entropy carbide ceramic materials with better friction properties at high temperatures. Summary of the Invention

[0006] The first object of the present invention is to provide a dense single-phase high-entropy carbide ceramic with excellent high-temperature friction performance to solve the problems raised in the above background technology.

[0007] The chemical formula of high entropy carbide ceramics is (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )C, the crystal structure is face-centered cubic structure.

[0008] Furthermore, the high entropy carbide ceramics of the present invention are prepared using TiO2, ZrO2, Nb2O5, MoO3, WO3 and graphite as raw materials.

[0009] Another object of the present invention is to provide a method for preparing the high entropy carbide ceramic. The preparation method comprises the following steps: 1) Calculate and weigh the metal oxide raw material powders TiO2, ZrO2, Nb2O5, MoO3, WO3 and graphite powder according to the stoichiometric ratio of 2:2:1:2:2:35. 2) The metal oxide raw material powder and graphite powder are ball-milled and mixed, pressed into blocks and then vacuum heat treated; 3) The raw materials after vacuum heat treatment are ball-milled again and then placed into a graphite mold for hot pressing and sintering to obtain high-entropy carbide ceramics.

[0010] Preferably, in step 1), the purity of the metal oxide raw material powder and the graphite powder are both ≥99.5%, and the particle size is 1-3 microns.

[0011] Preferably, in step 2), during the vacuum heat treatment, the temperature is raised to the heat treatment temperature at 5-10°C / min and then kept warm. The heat treatment temperature is not lower than 1500°C, and the holding time is not less than 1.5 h; the vacuum degree is not greater than 5 Pa.

[0012] Preferably, in step 3), the hot pressing sintering is carried out in a vacuum furnace, the temperature is raised to the sintering temperature at 3-10°C / min and then kept warm, and the sintering temperature is not lower than 1900°C; the pressure of the hot pressing sintering is not less than 40 MPa; and the vacuum degree is not greater than 5 Pa.

[0013] More preferably, in step 3), the heating rate is 10°C / min below 1000°C; the heating rate is 8°C / min between 1000°C and 1500°C; and the heating rate is 5°C / min above 1500°C.

[0014] The present invention achieves high-purity, single-phase carbide ceramic powder by regulating sintering parameters. Low sintering temperatures, short holding times, and slow heating rates prevent the reaction conditions from being met, leading to incomplete reaction between the raw materials, incomplete solid solution formation, and failure to form single-phase carbide ceramics. Excessively high heating rates make it difficult to control the reaction process, resulting in poor product performance and the potential for accidents.

[0015] Preferably, in step 2), roller ball milling is used, with a rotation speed of 80-120 rpm, a time of 24-36 h, zirconia balls as the grinding balls, anhydrous ethanol as the ball-to-material ratio of 2:1.

[0016] Preferably, in step 3), a planetary ball mill is used, with a rotation speed of 150-300 rpm, a time of 8-16 h, tungsten carbide balls, anhydrous ethanol as the ball milling medium, and a ball-to-material ratio of 2:1.

[0017] The present invention produces high-purity single-phase carbide ceramic powder by regulating ball milling parameters. Excessively high milling speeds, excessively long milling times, or excessively high ball-to-material ratios can lead to the incorporation of milling media into the prepared ceramic powder, contaminating the product. However, excessively low milling speeds, excessively short milling times, or excessively low ball-to-material ratios can lead to uneven mixing of the raw material powders, incomplete reaction, and the inability to produce single-phase carbide ceramics.

[0018] It should be noted that, in the high-temperature sintering process of the present invention, the equipment that can provide high-temperature conditions includes but is not limited to a vacuum hot pressing furnace, a spark plasma sintering furnace, a high-temperature graphitization furnace and the like, as long as the vacuum degree, temperature, holding time, heating rate and other equipment required in the sintering process are met; in the sample crushing process of the present invention, the means adopted include but are not limited to ball milling, manual grinding using a mortar, etc., as long as the powder reaches a particle size that meets the requirements of the experiment.

[0019] Another object of the present invention is to provide applications for the high-entropy carbide ceramics described above. These include applications in aerospace engine hot-end components, turbine engine seal rings and blade tips, friction plates for aircraft brake systems, bearings for transmissions in heat treatment furnaces in steel mills, turbine blade tenons and turbine disk seals for heavy-duty gas turbines, and high-temperature nozzles for laser cutting equipment.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses TiO2, ZrO2, Nb2O5, MoO3, WO3 and graphite as raw materials. The raw materials are widely available and low in price. They are cheaper than pure metal powder raw materials and metal carbide raw materials and are more suitable for industrial applications.

[0021] (2) The present invention starts from transition metal oxides and graphite raw materials, and adopts a method of hot pressing sintering after a high-temperature carbon thermal reduction reaction under vacuum, which effectively reduces the sintering temperature and solves the problems of low density and poor mechanical properties produced by direct hot pressing sintering, as well as the problems of impurities or excessive particle size introduced during the acquisition of high entropy ceramic powder.

[0022] (3) The present invention adopts a carbon thermal reduction reaction in a vacuum environment to solve the problem of low diffusion coefficient of carbides and difficulty in forming multi-component solid solutions.

[0023] The single-phase high entropy (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )C carbide ceramics have a dense structure and no impurity phases; there are a large number of carbon vacancies and lattice distortion caused by high entropy inside, and the local stress field generated by the distortion hinders dislocation slip, thereby improving the strength and hardness of the material; reasonable composition design and the presence of Mo lubricating phase make the high-temperature friction performance excellent, making the above-mentioned dense single-phase high entropy (Ti) with excellent high-temperature friction performance 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2)C carbide ceramics have a wider range of applications, such as aerospace engine hot end components (turbine engine sealing rings and blade tips), as well as friction plates in aircraft brake systems and transmission devices in steel plant heat treatment furnaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 For Example 1 (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )X-ray diffraction pattern of C high entropy carbide ceramics.

[0025] Figure 2 For Example 1 (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )Scanning electron microscope image of C high entropy carbide ceramic precursor.

[0026] Figure 3 For Example 1 (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )C Friction coefficient curve of high entropy carbide ceramics at different temperatures.

[0027] Figure 4 For Example 1 (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 ) Two-dimensional contour curve of wear scar of C high entropy carbide ceramic.

[0028] Figure 5 For Example 2 (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )X-ray diffraction pattern of C high entropy carbide ceramics.

[0029] Figure 6 For Example 3 (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )X-ray diffraction pattern of C high entropy carbide ceramics.

[0030] Figure 7 This is the X-ray diffraction pattern of the carbide ceramic of Comparative Example 1.

[0031] Figure 8 This is the X-ray diffraction pattern of the carbide ceramic of Comparative Example 2. DETAILED DESCRIPTION

[0032] The following describes the solution of the present invention in detail with reference to specific examples.

[0033] Example 1: The raw material powders of TiO2, ZrO2, Nb2O5, MoO3, WO3, and graphite powder were weighed and calculated in a stoichiometric ratio of 2:2:1:2:2:35. Their particle size was 1-3 μm and their purity was ≥99.9%. The raw material powders, zirconium oxide balls, and anhydrous ethanol were then added to a ball mill in a ratio of 1:2:1. The milling time was 24 hours and the speed was 100 rpm, respectively. After ball milling, the mixture was dried in an oven at 65°C for 6 hours and sieved to obtain a mixed powder.

[0034] The mixed powder was pressed into a block, placed in a graphite crucible, and subjected to carbon thermal reduction reaction in a vacuum hot pressing furnace. The vacuum degree in the furnace was less than 5 Pa. The temperature was raised to 1650 °C for heat treatment. After keeping the temperature for 2 h, the temperature was lowered to 1000 °C at a rate of 10 °C / min, and finally cooled to room temperature in the furnace.

[0035] The heat-treated sample was added to a ball mill in a ratio of 1:2:1, with the raw material powder, tungsten carbide balls, and anhydrous ethanol, respectively. The milling time and speed were 12 hours and 200 rpm, respectively. After ball milling, the sample was placed in an oven and dried at 65°C for 6 hours. The sample was then sieved through a 200-mesh sieve to obtain the heat-treated sample powder.

[0036] The heat-treated powder was placed in a graphite mold with a diameter of 20 mm and hot-pressed at 2000 °C for 2 h at a pressure of 40 MPa. The temperature was lowered to 1000 °C at a rate of 10 °C / min and then cooled to room temperature. High entropy carbide (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )C ceramics.

[0037] The prepared (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )C high entropy carbide ceramics have a single-phase face-centered cubic crystal structure, and the six elements Ti, Zr, Nb, Mo, W, and C are evenly distributed.

[0038] The (Ti 0.2 Zr 0.2 Nb 0.2Mo 0.2 W 0.2 )C high entropy carbide ceramics have a Vickers hardness of 34 GPa and a fracture toughness of 5.54 MPa·m 1 / 2 The (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 The friction coefficients of )C high entropy carbide ceramics at 25 ℃, 300 ℃, 600 ℃ and 900 ℃ are 0.42, 0.83, 0.91 and 0.62, respectively, and the wear rates are 4.56×10 -5 mm 3 / (N·m),2.43×10 -5 mm 3 / (N·m),1.65×10 -6 mm 3 / (N·m),3.5×10 - 6 mm 3 The high entropy carbide ceramic of the present invention has excellent mechanical properties and exhibits good friction properties at high temperatures, and can be used in the fields of high-temperature nozzles of rocket engines and thermal insulation coatings.

[0039] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

[0040] Example 2: The raw material powders of TiO2, ZrO2, Nb2O5, MoO3, WO3, and graphite were weighed and calculated in a stoichiometric ratio of 2:2:1:2:2:35. Their particle size was 1-3 μm and their purity was ≥99.9%. The raw material powders, zirconia balls, and anhydrous ethanol were then added to a ball mill in a ratio of 1:2:1. The milling process was performed for 24 hours at 100 rpm. After ball milling, the mixture was dried in an oven at 65°C for 6 hours and sieved to obtain a mixed powder.

[0041] The mixed powder was pressed into a block, placed in a graphite crucible, and subjected to carbon thermal reduction reaction in a vacuum hot pressing furnace. The vacuum degree in the furnace was less than 5 Pa, and the temperature was raised to 1600 °C for heat treatment. After keeping the temperature for 2 h, the temperature was lowered to 1000 °C at a rate of 10 °C / min, and finally cooled to room temperature in the furnace.

[0042] The heat-treated sample was added to a ball mill in a ratio of 1:2:1, with the raw material powder, tungsten carbide balls, and anhydrous ethanol, respectively. The milling time and speed were 12 hours and 200 rpm, respectively. After ball milling, the sample was placed in an oven and dried at 65°C for 6 hours. The sample was then sieved through a 200-mesh sieve to obtain the heat-treated sample powder.

[0043] The heat-treated powder was placed in a graphite mold with a diameter of 20 mm and hot-pressed at 1900 °C for 2 h at a pressure of 40 MPa. The temperature was lowered to 1000 °C at a rate of 10 °C / min and then cooled to room temperature. The (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )C high entropy carbide ceramics.

[0044] The prepared (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )C high entropy carbide ceramics have a single-phase face-centered cubic crystal structure, and the six elements Ti, Zr, Nb, Mo, W, and C are evenly distributed among each other.

[0045] Example 3: The raw material powders of TiO2, ZrO2, Nb2O5, MoO3, WO3, and graphite were weighed and calculated in a stoichiometric ratio of 2:2:1:2:2:35. Their particle size was 1-3 μm and their purity was ≥99.9%. The raw material powders, zirconia balls, and anhydrous ethanol were then added to a ball mill in a ratio of 1:2:1. The milling process was performed for 24 hours at 100 rpm. After ball milling, the mixture was dried in an oven at 65°C for 6 hours and sieved to obtain a mixed powder.

[0046] The mixed powder was pressed into a block, placed in a graphite crucible, and subjected to carbon thermal reduction reaction in a vacuum hot pressing furnace. The vacuum degree in the furnace was less than 5 Pa. The temperature was raised to 1550 °C for heat treatment. After keeping the temperature for 2 h, the temperature was lowered to 1000 °C at a rate of 10 °C / min, and finally cooled to room temperature in the furnace.

[0047] The heat-treated sample was added to a ball mill in a ratio of 1:2:1, with the raw material powder, tungsten carbide balls, and anhydrous ethanol, respectively. The milling time and speed were 12 hours and 200 rpm, respectively. After ball milling, the sample was placed in an oven and dried at 65°C for 6 hours. The sample was then sieved through a 200-mesh sieve to obtain the heat-treated sample powder.

[0048] The heat-treated powder was placed in a graphite mold with a diameter of 20 mm and hot-pressed at 2000 °C for 2 h at a pressure of 40 MPa. The temperature was lowered to 1000 °C at a rate of 10 °C / min and then cooled to room temperature. The (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )C high entropy carbide ceramics.

[0049] The prepared (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )C high entropy carbide ceramics have a single-phase face-centered cubic crystal structure, and the six elements Ti, Zr, Nb, Mo, W, and C are evenly distributed among each other.

[0050] Comparative Example 1: The raw material powders of TiO2, ZrO2, Nb2O5, MoO3, WO3, and graphite were weighed and calculated in a stoichiometric ratio of 2:2:1:2:2:35. Their particle size was 1-3 μm and their purity was ≥99.9%. The raw material powders, zirconia balls, and anhydrous ethanol were then added to a ball mill in a ratio of 1:2:1. The milling process was performed for 24 hours at 100 rpm. After ball milling, the mixture was dried in an oven at 65°C for 6 hours and sieved to obtain a mixed powder.

[0051] The mixed powder was pressed into a block, placed in a graphite crucible, and subjected to carbon thermal reduction reaction in a vacuum hot pressing furnace. The vacuum degree in the furnace was less than 5 Pa. The temperature was raised to 1650 °C for heat treatment. After keeping the temperature for 2 h, the temperature was lowered to 1000 °C at a rate of 10 °C / min, and finally cooled to room temperature in the furnace.

[0052] The heat-treated sample was added to a ball mill in a ratio of 1:2:1, with the raw material powder, tungsten carbide balls, and anhydrous ethanol, respectively. The milling time and speed were 12 hours and 200 rpm, respectively. After ball milling, the sample was placed in an oven and dried at 65°C for 6 hours. The sample was then sieved through a 200-mesh sieve to obtain the heat-treated sample powder.

[0053] The heat-treated powder was loaded into a graphite mold with a diameter of 20 mm and hot-pressed at 2000 °C for 2 h at a pressure of 40 MPa. The temperature was reduced to 1000 °C at a rate of 10 °C / min and then cooled to room temperature in the furnace. Carbide ceramics were then taken out.

[0054] like Figure 7As shown in Figure 3, the prepared carbide ceramics exhibit diffraction peaks of NbC and Mo2C, indicating that the ceramic is a mixture of these two substances, indicating that a single phase solid solution of carbide cannot be formed during the sintering process.

[0055] Comparative Example 2: The raw material powders of TiO2, ZrO2, Nb2O5, MoO3, WO3, and graphite were weighed and calculated in a stoichiometric ratio of 2:2:1:2:2:35. Their particle size was 1-3 μm and their purity was ≥99.9%. The raw material powders, zirconia balls, and anhydrous ethanol were then added to a ball mill in a ratio of 1:2:1. The milling process was performed for 24 hours at 100 rpm. After ball milling, the mixture was dried in an oven at 65°C for 6 hours and sieved to obtain a mixed powder.

[0056] The mixed powder was loaded into a graphite mold with a diameter of 20 mm for hot pressing and sintering. The sintering procedure was to first heat the temperature to 1600 °C and keep it for 2 h, then heat it to 2000 °C and keep it for 2 h. The whole process pressure was 40 MPa, and then it was reduced to 1000 °C at a rate of 10 °C / min. After that, it was cooled to room temperature in the furnace and taken out to obtain carbide ceramics.

[0057] like Figure 8 As shown in Figure 3, the prepared carbide ceramics exhibit diffraction peaks of NbC, Mo2C and WC, indicating that the ceramic is a mixture of these three substances, indicating that a single phase solid solution of carbide cannot be formed during the sintering process.

[0058] like Figure 1 、 Figure 5 、 Figure 6 According to the diffraction patterns of Examples 1-3, single-phase high entropy carbide ceramics were prepared. Figure 7 The diffraction pattern of the comparative example 1 shows that no single-phase carbide ceramics were obtained, indicating that a single-phase high-entropy carbide ceramic cannot be formed when the sintering temperature is lower than 1900°C.

[0059] Figure 2 This is a scanning electron microscope image of the high entropy carbide ceramic precursor obtained after vacuum heat treatment in Example 1, showing that the density of the sample after vacuum heat treatment is very high.

[0060] Figure 3 、 Figure 4 The friction performance of the high entropy carbide ceramics prepared in Example 1 under different temperature conditions is shown. The wear rate at 900 °C is only 3.5×10 -6 mm 3 / (N·m), relative to the (TiVNbMoW)C disclosed in Document 1 4.375 The wear rate at 800℃ is 3.4×10 -4 mm 3 / (N·m), the wear rate of (HfMoNbTaTi)C at 900 ℃ disclosed in Document 2 is 1×10 -4 mm 3 / (N·m), which is at least two orders of magnitude lower, proving that it has excellent high-temperature friction performance and is suitable for extreme environments, especially high-temperature friction environments, such as turbine engine sealing rings and blade tips, friction plates in aviation brake systems, bearings in transmission devices of heat treatment furnaces in steel plants, turbine blade tenons and turbine disk sealing rings of heavy-duty gas turbines, and high-temperature nozzles of laser cutting equipment.

Claims

1. A high entropy carbide ceramic, characterized in that: The chemical formula is (Ti 0.2 Zr 0.2 Nb 0.2 Mo 0.2 W 0.2 )C, the crystal structure is face-centered cubic structure.

2. The high entropy carbide ceramic according to claim 1, characterized in that It is prepared using TiO2, ZrO2, Nb2O5, MoO3, WO3 and graphite as raw materials.

3. A method for preparing a high entropy carbide ceramic according to claim 2, characterized in that: The following steps are involved: 1) Calculate and weigh the metal oxide raw material powders TiO2, ZrO2, Nb2O5, MoO3, WO3 and graphite powder according to the stoichiometric ratio of 2:2:1:2:2:

35. 2) The metal oxide raw material powder and graphite powder are ball-milled and mixed, pressed into blocks and then vacuum heat treated; 3) The raw materials after vacuum heat treatment are ball-milled again and then placed into a graphite mold for hot pressing and sintering to obtain high-entropy carbide ceramics.

4. The method for preparing high entropy carbide ceramics according to claim 3, wherein: In step 1), the purity of the metal oxide raw material powder and the graphite powder are both ≥99.5%, and the particle size is 1-3 microns.

5. The method for preparing high entropy carbide ceramics according to claim 3, wherein: In step 2), during vacuum heat treatment, the temperature is raised at 5-10°C / min to the heat treatment temperature and then kept warm. The heat treatment temperature is not lower than 1500°C, and the holding time is not less than 1.5 h; the vacuum degree is not greater than 5 Pa.

6. The method for preparing high entropy carbide ceramics according to claim 3, characterized in that: In step 3), hot pressing sintering is carried out in a vacuum furnace, the temperature is raised to the sintering temperature at 3-10°C / min and then kept warm, and the sintering temperature is not lower than 1900°C; the pressure of hot pressing sintering is not less than 40 MPa; and the vacuum degree is not greater than 5 Pa.

7. The method for preparing high entropy carbide ceramics according to claim 3, characterized in that: In step 2), roller ball milling is used at a rotation speed of 80-120 rpm for 24-36 h, the grinding balls are zirconia balls, the ball milling medium is anhydrous ethanol, and the ball-to-material ratio is 2:

1.

8. The method for preparing high entropy carbide ceramics according to claim 3, characterized in that: In step 3), a planetary ball mill is used with a rotation speed of 150-300 rpm for 8-16 h, the grinding balls are tungsten carbide balls, the ball milling medium is anhydrous ethanol, and the ball-to-material ratio is 2:

1.

9. An application of the high entropy carbide ceramic according to any one of claims 1 to 2, characterized in that: Used in hot end components of aerospace engines; or used in turbine engine sealing rings and blade tips; or used in friction plates of aircraft brake systems; or used in bearings in transmission devices of heat treatment furnaces in steel plants; or used in turbine blade tenons and turbine disk sealing rings of heavy-duty gas turbines; or used in high-temperature nozzles of laser cutting equipment.

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