A high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio, high hardness and high elastic modulus and a preparation method thereof

Abstract

The present application relates to a kind of high-entropy carbonitride ceramics with controllable carbon-nitrogen ratio, high hardness and high elastic modulus and a preparation method thereof, and belongs to the technical field of high-entropy ceramics.To solve the problem that existing preparation methods cannot simultaneously control carbon-nitrogen ratio and mechanical properties of high-entropy carbonitride ceramics, the present application obtains a mixed powder by ball milling and drying Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder and carbon black;obtains ceramic powder by heat treatment of the mixed powder in a nitrogen atmosphere;and obtains high-entropy carbonitride ceramics by spark plasma sintering of the ceramic powder.By adjusting the molar ratio of metal powder to carbon black, the present application controls the carbon vacancy concentration of high-entropy system, and then realizes the introduction of nitrogen atoms, which makes it easier to control the carbon-nitrogen ratio of ceramic powder.Spark plasma sintering can effectively avoid grain growth, and obtain dense fine-grained high-entropy carbonitride ceramics in a relatively short time, which is conducive to the improvement of mechanical properties of high-entropy carbonitride ceramics.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-entropy ceramics, and relates to a manufacturing method of special ceramic products, in particular to a high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio, high hardness and high elastic modulus and a preparation method thereof. BACKGROUND

[0002] Compared with traditional binary ceramics, high-entropy ceramics have more excellent oxidation resistance, mechanical properties and thermophysical properties, and have become a research hotspot at home and abroad in recent years. At present, the researches at home and abroad mainly focus on mononegative high-entropy ceramics such as borides, carbides and nitrides. Compared with mononegative high-entropy ceramics, polyanionic high-entropy ceramics have relatively higher configuration entropy due to the increase in the number of anions, and exhibit a broader performance control space and designability. High-entropy carbonitride has the same face-centered cubic crystal structure as the corresponding mononegative high-entropy ceramic, is easier to synthesize than high-entropy borocarbide, and is more outstanding in mechanical properties, and therefore has great application prospects in the field of super-high-temperature thermal protection.

[0003] The carbon-nitrogen ratio of high-entropy carbonitride has an important influence on the composition, structure and performance of the ceramic. For example, as the carbon-nitrogen ratio increases, the hardness and modulus increase, and the fracture toughness decreases. Therefore, it is of great significance to explore a ceramic preparation method with controllable carbon-nitrogen ratio. The synthesis methods of high-entropy carbonitride ceramic powder mainly include carbothermal reduction-nitridation method, sol-gel-nitridation method, mechanical alloying-nitridation method and solid solution reaction method. The carbothermal reduction-nitridation method using metal oxides, carbon black and nitrogen as starting materials and the sol-gel-nitridation method using metal oxides, metal chlorides or metal salts as metal sources, carbon black or organic matter as carbon source and nitrogen as nitrogen source are difficult to control the carbon-nitrogen ratio. The mechanical alloying-nitridation method using metal elements, carbon black and nitrogen as starting materials and the solid solution reaction method using single-component metal carbide and metal nitride as starting materials are relatively easy to control the carbon-nitrogen ratio. Compared with the solid solution reaction method, the mechanical alloying-nitridation method has lower cost, but the ceramic powder synthesized by this method has a larger particle size, which will adversely affect the sintering performance of the ceramic. Reducing the heat treatment temperature of the ceramic powder can reduce the particle size of the powder, but it is not conducive to the phase solid solution of the ceramic powder, and will adversely affect the chemical stability and density of the ceramic. SUMMARY

[0004] To solve the problem that the existing preparation method cannot simultaneously control the carbon-nitrogen ratio and the mechanical properties of high-entropy carbonitride ceramic, the application provides a high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio, high hardness and high elastic modulus and a preparation method thereof.

[0005] The technical scheme of the application is as follows:

[0006] The application discloses a preparation method of high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio, high hardness and high elastic modulus.

[0007] Further, the molar ratio of the Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder and carbon black is 2:(2-4):(2-4):(0.5-1.5):(0.5-1.5):(5-9).

[0008] Further, the particle size of the Ti powder, ZrH2 powder, Hf powder, Ta powder and Cr powder is 5-10 microns, the particle size of the carbon black is 1-3 microns, and the purity of the Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder and carbon black is higher than 99.5%.

[0009] Further, the medium of the mixing ball milling is alcohol, the ball-to-material ratio is 4-6:1, the ball milling rotation speed is 200-300 r / min, and the ball milling time is 20-30 hours.

[0010] Further, the drying temperature is 80-100 DEG C, and the drying time is 6-8 hours.

[0011] Further, the heat treatment is to heat to 1500-1600 DEG C at a heating rate of 3-5 DEG C / min, keep warm for 1-2 hours, and then cool to room temperature at a cooling rate of 3-5 DEG C / min.

[0012] Further, the particle size of the ceramic powder is 3-7 microns.

[0013] Further, the discharge plasma sintering is carried out under vacuum, heated to 1800-1900 DEG C at a heating rate of 80-100 DEG C / min, kept warm for 10-15 minutes, cooled to 200-300 DEG C at a cooling rate of 10-20 DEG C / min, and then naturally cooled to room temperature, and the sintering pressure is 30-40 MPa.

[0014] Further, the discharge plasma sintering is carried out under vacuum, heated to 1700-1750 DEG C at a heating rate of 80-100 DEG C / min, kept warm for 5-10 minutes, heated to 1800-1900 DEG C at a heating rate of 80-100 DEG C / min again, kept warm for 5-10 minutes, cooled to 200-300 DEG C at a cooling rate of 10-20 DEG C / min, and then naturally cooled to room temperature, and the sintering pressure is 30-40 MPa.

[0015] The high-entropy carbonitride ceramic prepared by the preparation method has a controllable carbon-nitrogen ratio, a high hardness and a high elastic modulus, and the grain size of the high-entropy carbonitride ceramic is 2-3 μm.

[0016] The present application has the following beneficial effects:

[0017] The preparation method of the high-entropy carbonitride ceramic provided by the present application uses metal element powder and metal hydride powder as metal sources, carbon black as a carbon source, and nitrogen as a nitrogen source, and combines the exothermic reaction of the metal element powder and the carbon black at high temperature with nitriding heat treatment to synthesize ceramic powder. The present application adjusts the molar ratio of the metal powder and the carbon black to control the carbon vacancy concentration of the high-entropy system, and then realizes the introduction of nitrogen atoms, which is more conducive to the control of the carbon-nitrogen ratio of the ceramic powder. The present application uses spark plasma sintering to realize the further solid solution of the ceramic powder and the preparation of the high-entropy carbonitride ceramic, which can effectively avoid grain growth and obtain dense fine-grained high-entropy carbonitride ceramic in a relatively short time, which is conducive to the improvement of the mechanical properties of the high-entropy carbonitride ceramic. The high-entropy carbonitride ceramic prepared by the present application has a Vickers hardness of 20.12-22.04 GPa and an elastic modulus of 479-510 GPa. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The XRD pattern of the high-entropy carbonitride ceramic prepared in Example 3 is shown in the figure.

[0019] Figure 2 The SEM pattern of the fracture surface of the high-entropy carbonitride ceramic prepared in Example 3 is shown in the figure.

[0020] Figure 3 The SEM pattern of the corresponding ceramic powder of the high-entropy carbonitride ceramic prepared in Example 3 is shown in the figure.

[0021] Figure 4 The comparison chart of the carbon-nitrogen ratio, Vickers hardness and elastic modulus of the high-entropy carbonitride ceramic prepared in Examples 1-7 is shown in the figure. DETAILED DESCRIPTION

[0022] The technical solutions of the present application are further described below in conjunction with the examples, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present application without departing from the spirit and scope of the technical solutions of the present application shall be covered in the protection scope of the present application. The process equipment or device not specifically mentioned in the following examples is the conventional equipment or device in the art. If not specifically mentioned, the raw materials used in the examples of the present application are commercially available. If not specifically mentioned, the technical means used in the examples of the present application is the conventional means known to those skilled in the art.

[0023] Example 1

[0024] The embodiment provides a preparation method of high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio, high hardness and high elastic modulus.

[0025] The high-entropy carbonitride ceramic is prepared according to the following steps in the embodiment:

[0026] Step one, mixing raw material powders:

[0027] The raw material powders used in the embodiment are Ti powders, ZrH2 powders, Hf powders, Ta powders and Cr powders with particle size distribution of 5-10 μm and purity higher than 99.5%, and carbon black with particle size distribution of 1-3 μm and purity higher than 99.5%.

[0028] The raw material powders are mixed according to the molar ratio of Ti powders, ZrH2 powders, Hf powders, Ta powders, Cr powders and carbon black as 2:2:2:0.5:0.5:5, the mixing mode is ball milling, the ball milling medium is alcohol, the ball-to-material ratio is 4:1, the ball milling speed is 240 r / min, and the ball milling time is 30 h. After ball milling, the collected powders are placed in a vacuum drying box and dried at 80 ℃ for 8 h to obtain mixed powders.

[0029] Step two, synthesizing ceramic powders:

[0030] The mixed powders obtained in step one are placed in a nitrogen atmosphere and subjected to heat treatment, the temperature is increased to 1500 ℃ at a rate of 5 ℃ / min and kept for 2 h, then the temperature is decreased to room temperature at a rate of 5 ℃ / min, the heat-treated powders are ground to obtain ceramic powders with a particle size of 4.46±1.33 μm.

[0031] Step three, preparing high-entropy carbonitride ceramic:

[0032] The ceramic powders obtained in step two are placed in a graphite mold with good thermal conductivity and lined with graphite paper, and subjected to spark plasma sintering under vacuum conditions, the sintering pressure is 30 MPa, the temperature is increased to 1720 ℃ at a rate of 80 ℃ / min and kept for 7 min, then the temperature is increased to 1820 ℃ at a rate of 100 ℃ / min and kept for 8 min, then the temperature is decreased to 250 ℃ at a rate of 20 ℃ / min, and finally the temperature is decreased to room temperature naturally, to obtain high-entropy carbonitride ceramic with a grain size of 2.29±0.69 μm.

[0033] Embodiment 2

[0034] The embodiment provides a preparation method of high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio, high hardness and high elastic modulus, and the carbon-nitrogen ratio of the high-entropy carbonitride ceramic in the embodiment is 2.92.

[0035] The high-entropy carbonitride ceramic is prepared according to the following steps:

[0036] Step one, mixing raw material powders:

[0037] The raw material powders used in this embodiment are Ti powder, ZrH2 powder, Hf powder, Ta powder and Cr powder with a particle size distribution of 5-10 μm and a purity higher than 99.5%, and carbon black with a particle size distribution of 1-3 μm and a purity higher than 99.5%.

[0038] The raw material powders are mixed according to the molar ratio of Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder and carbon black as 2:2.5:2.5:0.75:0.75:6, the mixing method is ball milling, the ball milling medium is alcohol, the ball-to-material ratio is 6:1, the ball milling speed is 300 r / min, and the ball milling time is 25 h. After ball milling, the collected powders are placed in a vacuum drying box and dried at 100 ℃ for 6 h to obtain the mixed powders.

[0039] Step two, synthesizing ceramic powders:

[0040] The mixed powders obtained in step one are placed in a nitrogen atmosphere and heat treated at a heating rate of 3 ℃ / min to 1550 ℃ and kept for 2 h, and then cooled to room temperature at a cooling rate of 3 ℃ / min. The heat treated powders are ground to obtain ceramic powders with a particle size of 4.41±1.39 μm.

[0041] Step three, preparing high-entropy carbonitride ceramic:

[0042] The ceramic powders obtained in step two are placed in a graphite mold with good thermal conductivity and lined with graphite paper, and subjected to spark plasma sintering under vacuum conditions at a sintering pressure of 40 MPa, a heating rate of 100 ℃ / min to 1750 ℃ and a holding time of 7 min, a heating rate of 100 ℃ / min to 1850 ℃ and a holding time of 8 min, a cooling rate of 15 ℃ / min to 300 ℃, and finally natural cooling to room temperature. The high-entropy carbonitride ceramic with a grain size of 2.38±0.65 μm is obtained.

[0043] Embodiment 3

[0044] The embodiment provides a preparation method of high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio and high hardness and high elastic modulus. The carbon-nitrogen ratio of the high-entropy carbonitride ceramic in the embodiment is 2.87.

[0045] The high-entropy carbonitride ceramic is prepared according to the following steps:

[0046] Step one, mixing raw material powders:

[0047] The raw material powder used in this embodiment is Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder, and carbon black, all with a particle size distribution of 5-10 μm and a purity of more than 99.5%, and carbon black with a particle size distribution of 1-3 μm and a purity of more than 99.5%.

[0048] The raw material powder is mixed in a molar ratio of 2:3:3:1:1:7, with Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder, and carbon black. The mixing method is ball milling, the ball milling medium is alcohol, the ball-to-powder ratio is 5:1, the ball milling speed is 280 r / min, and the ball milling time is 24 h. After ball milling, the powder is collected and placed in a vacuum drying oven, dried at 90°C for 7 h, and mixed powder is obtained.

[0049] Step two, synthesis of ceramic powder:

[0050] The mixed powder obtained in step one is placed in a nitrogen atmosphere and heat treated at a heating rate of 5°C / min to 1550°C and held for 2 h, then cooled at a cooling rate of 3°C / min to room temperature. The heat treated powder is ground to obtain ceramic powder with a particle size of 4.34±1.31 μm.

[0051] Step three, preparation of high-entropy carbonitride ceramic:

[0052] The ceramic powder obtained in step two is placed in a graphite mold with good thermal conductivity and lined with graphite paper, and subjected to spark plasma sintering under vacuum conditions. The sintering pressure is 35 MPa, the heating rate is 100°C / min to 1750°C and held for 7 min, then the heating rate is 80°C / min to 1850°C and held for 8 min, then the cooling rate is 12°C / min to 250°C, and finally naturally cooled to room temperature. A high-entropy carbonitride ceramic with a grain size of 2.26±0.63 μm is obtained.

[0053] Example 4

[0054] This embodiment provides a method for preparing a high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio and high hardness and high elastic modulus. The carbon-nitrogen ratio of the high-entropy carbonitride ceramic in this embodiment is 2.81.

[0055] This embodiment prepares a high-entropy carbonitride ceramic according to the following steps:

[0056] Step one, mixing of raw material powder:

[0057] The raw material powder used in this embodiment is Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder, and carbon black, all with a particle size distribution of 5-10 μm and a purity of more than 99.5%, and carbon black with a particle size distribution of 1-3 μm and a purity of more than 99.5%.

[0058] The raw material powders were mixed in a molar ratio of 2:3.5:3.5:1.25:1.25:8 of Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder and carbon black, and the mixing method was ball milling, the ball milling medium was alcohol, the ball-to-powder ratio was 6:1, the ball milling speed was 300 r / min, and the ball milling time was 20 h. After ball milling, the powder was collected and placed in a vacuum drying oven, dried at 90℃ for 8 h, and mixed powder was obtained.

[0059] Step two, synthesis of ceramic powder:

[0060] The mixed powder obtained in step one was placed in a nitrogen atmosphere for heat treatment, heated to 1580℃ at a rate of 5℃ / min and kept for 1 h, then cooled to room temperature at a rate of 3℃ / min, and the heat-treated powder was ground to obtain ceramic powder with a particle size of 4.17±1.25μm.

[0061] Step three, preparation of high-entropy carbonitride ceramic:

[0062] The ceramic powder obtained in step two was placed in a graphite mold with good thermal conductivity and lined with graphite paper, and subjected to spark plasma sintering under vacuum conditions, with a sintering pressure of 40 MPa, a heating rate of 100℃ / min to 1850℃ and a holding time of 10 min, then cooled to 200℃ at a rate of 15℃ / min, and finally naturally cooled to room temperature, to obtain high-entropy carbonitride ceramic with a grain size of 2.34±0.73μm.

[0063] Example 5

[0064] This example provides a method for preparing high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio and high hardness and high elastic modulus, and the carbon-nitrogen ratio of the high-entropy carbonitride ceramic in this example is 2.89.

[0065] This example prepares high-entropy carbonitride ceramic according to the following steps:

[0066] Step one, mixing of raw material powders:

[0067] The raw material powders used in this example are Ti powder, ZrH2 powder, Hf powder, Ta powder and Cr powder with a particle size distribution of 5-10μm and a purity of more than 99.5%, and carbon black with a particle size distribution of 1-3μm and a purity of more than 99.5%.

[0068] The raw material powders were mixed in a molar ratio of 2:4:4:1.5:1.5:9 of Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder and carbon black, and the mixing method was ball milling, the ball milling medium was alcohol, the ball-to-powder ratio was 5:1, the ball milling speed was 280 r / min, and the ball milling time was 25 h. After ball milling, the powder was collected and placed in a vacuum drying oven at a temperature of 100℃ for 6 h to obtain the mixed powder.

[0069] Step two, synthesis of ceramic powder:

[0070] The mixed powder obtained in step one was placed in a nitrogen atmosphere and heat treated at a heating rate of 3℃ / min to 1550℃ and held for 2 h, then cooled to room temperature at a cooling rate of 5℃ / min. The heat treated powder was ground to obtain a ceramic powder with a particle size of 4.31±1.26μm.

[0071] Step three, preparation of high-entropy carbonitride ceramic:

[0072] The ceramic powder obtained in step two was placed in a graphite mold with good thermal conductivity and lined with graphite paper inside, and subjected to spark plasma sintering under vacuum conditions. The sintering pressure was 30 MPa, the heating rate was 90℃ / min to 1750℃ and held for 10 min, then the heating rate was 100℃ / min to 1850℃ and held for 5 min, then the cooling rate was 10℃ / min to 300℃, and finally naturally cooled to room temperature. A high-entropy carbonitride ceramic with a grain size of 2.25±0.66μm was obtained.

[0073] Example 6

[0074] The present embodiment provides a method for preparing a high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio and high hardness and high elastic modulus. In this embodiment, the carbon-nitrogen ratio of the high-entropy carbonitride ceramic is 2.27.

[0075] The high-entropy carbonitride ceramic was prepared according to the following steps in this embodiment:

[0076] Step one, mixing of raw material powders:

[0077] The raw material powders used in this embodiment were Ti powder, ZrH2 powder, Hf powder, Ta powder and Cr powder with a particle size distribution of 5-10μm and a purity of more than 99.5%, and carbon black with a particle size distribution of 1-3μm and a purity of more than 99.5%.

[0078] The raw material powders were mixed in a molar ratio of 2:3:3:1:1:6 of Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder and carbon black, and the mixing method was ball milling, the ball milling medium was alcohol, the ball-to-material ratio was 6:1, the ball milling speed was 300 r / min, and the ball milling time was 20 h. After ball milling, the powder was collected and placed in a vacuum drying oven, dried at 80°C for 8 h, and mixed powder was obtained.

[0079] Step two, synthesis of ceramic powder:

[0080] The mixed powder obtained in step one was placed in a nitrogen atmosphere for heat treatment, heated to 1580°C at a rate of 5°C / min and held for 2 h, then cooled to room temperature at a rate of 3°C / min, and the heat-treated powder was ground to obtain ceramic powder with a particle size of 3.91±1.21 μm.

[0081] Step three, preparation of high-entropy carbonitride ceramic:

[0082] The ceramic powder obtained in step two was placed in a graphite mold with good thermal conductivity and lined with graphite paper, and subjected to spark plasma sintering under vacuum conditions, with a sintering pressure of 40 MPa, a heating rate of 100°C / min to 1900°C and a holding time of 15 min, then cooled to 250°C at a rate of 15°C / min, and finally naturally cooled to room temperature, to obtain high-entropy carbonitride ceramic with a grain size of 2.40±0.71 μm.

[0083] Example 7

[0084] This example provides a method for preparing high-entropy carbonitride ceramic with controllable carbon-nitrogen ratio and high hardness and high elastic modulus. In this example, the carbon-nitrogen ratio of the high-entropy carbonitride ceramic is 4.35.

[0085] This example prepares high-entropy carbonitride ceramic according to the following steps:

[0086] Step one, mixing of raw material powders:

[0087] The raw material powders used in this example are Ti powder, ZrH2 powder, Hf powder, Ta powder and Cr powder with a particle size distribution of 5-10 μm and a purity of more than 99.5%, and carbon black with a particle size distribution of 1-3 μm and a purity of more than 99.5%.

[0088] The raw material powders were mixed in a molar ratio of 2:3:3:1:1:8 of Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder and carbon black, and the mixing method was ball milling, the ball milling medium was alcohol, the ball-to-material ratio was 5:1, the ball milling speed was 250 r / min, and the ball milling time was 24 h. After ball milling, the powder was collected and placed in a vacuum drying oven, dried at 80°C for 8 h, and mixed powder was obtained.

[0089] Step two, synthesis of ceramic powder:

[0090] The mixed powder obtained in step one was placed in a nitrogen atmosphere for heat treatment, heated to 1550°C at a heating rate of 5°C / min and kept for 2h, then cooled to room temperature at a cooling rate of 3°C / min, and the heat-treated powder was ground to obtain a ceramic powder with a particle size of 4.96±1.42μm.

[0091] Step three, preparation of high-entropy carbonitride ceramic:

[0092] The ceramic powder obtained in step two was placed in a graphite mold with good thermal conductivity and lined with graphite paper, and subjected to spark plasma sintering under vacuum conditions, with a sintering pressure of 40MPa, heated to 1900°C at a heating rate of 100°C / min and kept for 10min, then cooled to 250°C at a cooling rate of 15°C / min, and finally naturally cooled to room temperature, obtaining a high-entropy carbonitride ceramic with a grain size of 2.35±0.68μm.

[0093] Figure 1 XRD pattern (X-ray diffraction pattern) of the high-entropy carbonitride ceramic prepared in Example 3; from Figure 1 It can be seen that the ceramic is composed of a single (Ti, Zr, Hf, Ta, Cr) CN solid solution phase, and no other phases and oxide phases are found.

[0094] Figure 2 SEM image (scanning electron micrograph) of the fracture surface of the high-entropy carbonitride ceramic prepared in Example 3,

[0095] Figure 3 SEM image of the corresponding ceramic powder of the high-entropy carbonitride ceramic prepared in Example 3; from Figure 2 and Figure 3 It can be seen that the grain size of the high-entropy carbonitride ceramic is smaller than the particle size of the corresponding ceramic powder, which is due to the rapid densification of spark plasma sintering, which better inhibits grain growth.

[0096] Figure 4 Comparison chart of carbonitride ratio, Vickers hardness and elastic modulus of the high-entropy carbonitride ceramics prepared in Examples 1-7, from Figure 4 It can be seen that all the (Ti, Zr, Hf, Ta, Cr) CN high-entropy carbonitride ceramics prepared in the examples have high Vickers hardness and elastic modulus, and by adjusting the molar ratio of metal powder to carbon black, the carbonitride ratio of the (Ti, Zr, Hf, Ta, Cr) CN high-entropy carbonitride ceramic can be effectively controlled.

Claims

1. A method for preparing a high-entropy carbonitride ceramic with controllable carbon-to-nitrogen ratio, characterized in that, Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder, and carbon black were mixed, ball-milled, and dried to obtain a mixed powder. The mixed powder was then subjected to heat treatment under a nitrogen atmosphere. The heat treatment was performed by heating to 1500-1600℃ at a heating rate of 3-5℃ / min, holding for 1-2 hours, and then cooling to room temperature at a cooling rate of 3-5℃ / min to obtain ceramic powder. The ceramic powder was then subjected to spark plasma sintering under vacuum conditions, with the temperature increased to 18℃ at a heating rate of 80-100℃ / min. The sintering temperature is 00~1900℃, held for 10~15min, then cooled to 200~300℃ at a rate of 10~20℃ / min, and then allowed to cool naturally to room temperature. The sintering pressure is 30~40MPa. Alternatively, the spark plasma sintering is carried out under vacuum conditions, with the temperature increased to 1700~1750℃ at a rate of 80~100℃ / min, held for 5~10min, then increased to 1800~1900℃ at a rate of 80~100℃ / min, held for 5~10min, then cooled to 200~300℃ at a rate of 10~20℃ / min, and then allowed to cool naturally to room temperature. The sintering pressure is 30~40MPa, to obtain high-entropy carbonitride ceramics.

2. The method for preparing a high-hardness, high-elasticity, high-entropy carbonitride ceramic with controllable carbon-to-nitrogen ratio according to claim 1, characterized in that, The particle size of the Ti powder, ZrH2 powder, Hf powder, Ta powder, and Cr powder is 5~10μm, the particle size of the carbon black is 1~3μm, and the purity of the Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder, and carbon black is higher than 99.5%.

3. The method for preparing a high-hardness, high-elasticity, high-entropy carbonitride ceramic with controllable carbon-to-nitrogen ratio according to claim 2, characterized in that, The medium for the mixed ball milling is alcohol, the ball-to-material ratio is 4~6:1, the ball milling speed is 200~300 r / min, and the ball milling time is 20~30 h.

4. The method for preparing a high-hardness, high-elasticity, high-entropy carbonitride ceramic with controllable carbon-to-nitrogen ratio according to claim 3, characterized in that, The drying temperature is 80~100℃, and the drying time is 6~8h.

5. The method for preparing a high-entropy carbonitride ceramic with controllable carbon-to-nitrogen ratio, high hardness, and high elastic modulus according to claim 4, characterized in that, The particle size of the ceramic powder is 3~7μm.

6. A high-entropy carbonitride ceramic with controllable carbon-to-nitrogen ratio, high hardness, and high elastic modulus, prepared by the preparation method according to any one of claims 1-5, characterized in that, The high-entropy carbonitride ceramic has a grain size of 2~3μm.

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