A transition metal carbonitride-SiC x N y Composite ceramics and preparation method thereof

Abstract

The present invention discloses a transition metal carbonitride-SiC x N y Composite ceramics and a preparation method thereof, comprising: mixing MeSi2 powder and carbon powder and then ball-milling them uniformly, drying and further grinding them to obtain a fully mixed powder mixture; pressing the powder mixture into a ceramic body by a cold pressing process; subjecting the ceramic body to a high-temperature heat treatment in a nitrogen environment, and cooling the ceramic body to obtain a transition metal carbonitride-SiC x N y Composite ceramics. In the process of preparing transition metal carbonitride ceramics, SiC is generated simultaneously. x N y Compared with single-phase ceramics, due to the presence of the second phase, the sintering performance of multiphase ceramics has been greatly improved, and the strength and toughness have been improved. Silicon-based composite carbide ceramics also show better anti-ablation performance, realizing the wide temperature range and high temperature range application of transition metal carbonitrides.

Description

Technical Field

[0001] The present invention belongs to the field of transition metal carbonitride composite ceramics and relates to a transition metal carbonitride-SiC x N y Composite ceramics and preparation methods thereof. Background Art

[0002] As high-speed aircraft develop towards higher Mach, longer flight time and larger airspace, aircraft are subjected to extreme temperature differences and harsh aerodynamic / thermal environments during their service. This places more stringent requirements on thermal protection materials - more resistant to high temperatures, greater load-bearing capacity and greater erosion resistance to ensure safety and reliability during flight. Ultra-high temperature ceramics, mainly referring to carbides, nitrides and borides of group IVB and group VB transition metals, have excellent physical and chemical properties such as high melting point, high hardness, high modulus, high temperature resistance and good corrosion resistance. They have become important non-ablative thermal protection materials and are widely used in the nose tip, leading edge of the fuselage and key hot end components of the ramjet combustion chamber of high-speed aircraft. In the SHARPB-1 and B-2 hypersonic aircraft tests and related NASA reports, ultra-high temperature ceramics were identified as candidate materials for key thermal structural components of hypersonic aircraft. Studies have shown that introducing N atoms into the C sublattice of carbide ultra-high temperature ceramics can further improve the high temperature stability and ablation resistance of carbide ceramics, especially HfC x N y The ceramic system is predicted to have the highest melting point and is expected to be used in ultra-high temperature environments above 3000°C.

[0003] Currently, researchers have studied HfC x N y The preparation of powder or bulk ceramics was studied. x N 1-x Ceramic powders[J].Materials Chemistry and Physics, 2023, 295:127099. Hf, HfN, and C powders were used as raw materials and induction heated to 2400°C and kept warm for 30 minutes to prepare HfC. x N 1-xPowder. Reference 2 "Peng Zheng. Design, preparation and ablation resistance of ultra-high temperature hafnium carbonitride ceramics and their composite materials [D], 2022." Using high-purity HfC and HfN powders as raw materials, g-C3N4 powder as a supplementary carbon source and nitrogen source, the spark plasma sintering method was used and a pressure of 20 MPa was applied. The temperature was kept at 2200 ° C for 20 minutes to prepare ultra-high temperature HfC with a density of more than 99%. x N y However, currently HfC x N y The preparation conditions of ceramics are harsh and the preparation cost is high. In addition, the intrinsic brittleness and insufficient oxidation resistance of single-phase ultra-high temperature ceramics limit their engineering applications. Summary of the Invention

[0004] The purpose of the present invention is to provide a transition metal carbonitride-SiC x N y Composite ceramics and their preparation method solve the problems of HfC in the existing technology x N y The preparation conditions of ceramics are harsh and the application performance is insufficient.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A transition metal carbonitride-SiC x N y A method for preparing a composite ceramic comprises:

[0007] The MeSi2 powder and carbon powder are mixed and ball-milled uniformly, and then further ground after drying to obtain a fully mixed powder mixture;

[0008] Pressing the powder mixture into a ceramic body by cold pressing;

[0009] The ceramic body is subjected to high temperature heat treatment in a nitrogen environment, and transition metal carbonitride-SiC is obtained after cooling. x N y Composite ceramics;

[0010] In the MeSi2, Me is a transition metal.

[0011] Furthermore, in the MeSi2, Me is a mixture of one or more phases of Hf, Zr, Ta, Ni, and Ti.

[0012] Furthermore, the mixing molar ratio of the MeSi2 powder to the carbon powder is 1-5:1-5.

[0013] Furthermore, during the ball milling process, the ball-to-material ratio is 2:1, the ball milling medium is anhydrous ethanol, and the mass ratio of the anhydrous ethanol to the mixed powder of MeSi2 powder and carbon powder is 2 to 3:1.

[0014] Furthermore, during the ball milling process, the rotation speed is 200-500 rpm and the ball milling time is 4-6 hours.

[0015] Furthermore, the drying temperature is 60-100° C., and the drying time is 8-18 hours.

[0016] Furthermore, the cold pressing process includes:

[0017] The powder mixture is poured into a tabletting mold with a diameter of Φ10 to Φ30 mm, and the pressure is maintained at 4 to 15 MPa for 1 to 30 minutes to obtain a ceramic body with a diameter of Φ10 to Φ30 mm.

[0018] Furthermore, the heating rate of the high-temperature heat treatment is 2-10°C / min, the heat treatment temperature is 1500-1800°C, and the heat treatment time is 1-3h.

[0019] Furthermore, the cooling process is: cooling to 300° C. at a rate of 2-10° C., and then cooling to room temperature.

[0020] Transition metal carbonitride-SiC prepared by the preparation method x N y Composite ceramics.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a transition metal carbonitride-SiC x N y The preparation method of composite ceramics adopts nitriding heat treatment method, using transition metal disilicide and C powder as raw materials, and reacting at high temperature in nitrogen atmosphere to generate transition metal carbonitride-SiC x N y (y can be 0) composite ceramics. In the process of preparing transition metal carbonitride ceramics, SiC is generated simultaneously. x N y Compared with single-phase ceramics, the sintering performance of composite ceramics is greatly improved due to the presence of the second phase, and the strength and toughness are improved. In particular, silicon-based composite carbide ceramics have the advantages of a wide service temperature range and good process adaptability. At the same time, due to the self-healing effect of SiO2 and the formation of low oxygen permeability silicate glass, silicon-based composite carbide ceramics also show better anti-ablation performance, realizing the wide temperature range and high temperature range application of transition metal carbonitrides. Based on the present invention, transition metal carbonitride-SiC can be more widely designed.x N y Preparation and performance improvement solutions for composite ceramics, SiC x N y It has potential applications in electromagnetic microwaves. By designing the raw material ratio and process parameters, it is expected to achieve functional applications of this type of composite ceramics. Therefore, the development prospects of the present invention are very promising, and the economic and social benefits are very outstanding.

[0023] The present invention adopts the nitriding heat treatment method to prepare the transition metal carbonitride-SiC x N y The phase distribution of composite ceramics is uniform, compared with the existing HfC x N y Ceramic preparation process, HfC in the composite ceramic x N y The introduction method is simple and low cost. In high temperature oxygen environment, it has excellent ablation resistance. Transition metal carbonitrides have extremely high melting enthalpy, excellent high temperature stability and ablation resistance. In addition, SiC x N y The introduction of Si-Me-CN nanowires allows composite ceramics to be used in various high-temperature environments. Furthermore, the Si-Me-CN nanowires formed on the sample surface facilitate thermal conductivity, reducing the ablation surface temperature and further enhancing the composite ceramic's ablation resistance. Furthermore, compared to transition metal carbide or nitride ceramics, transition metal carbonitride ceramics possess higher hardness, a certain degree of toughness and ductility, and exhibit superior erosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 The transition metal carbonitride-SiC of the present invention x N y Flow chart of the preparation process of composite ceramics.

[0026] Figure 2 HfC prepared in Example 1 of the present invention x N y -SiC x N y Low-magnification SEM image of the composite ceramic.

[0027] Figure 3 HfC prepared in Example 1 of the present inventionx N y -SiC x N y High-magnification SEM image and corresponding EDS spectrum of the composite ceramic, where (a) is the high-magnification SEM image and (b) is the EDS spectrum.

[0028] Figure 4 HfC prepared in Example 1 of the present invention x N y -SiC x N y XRD pattern of composite ceramics.

[0029] Figure 5 HfC prepared in Example 2 of the present invention x N y -SiC x N y Macroscopic image of the surface of composite ceramics after oxyacetylene torch ablation.

[0030] Figure 6 HfC prepared in Example 3 of the present invention x N y -SiC x N y High-magnification SEM image of the cross-section of the composite ceramic. DETAILED DESCRIPTION

[0031] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0032] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0033] Herein, all features such as values, amounts, amounts, and concentrations defined in numerical ranges or percentage ranges are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0034] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0035] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0036] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0037] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0038] The present invention is described in further detail below with reference to the accompanying drawings:

[0039] See also Figure 1 The present invention provides a transition metal carbonitride-SiC x N y The preparation method of the composite ceramic comprises the following steps:

[0040] Step 1: Mix MeSi2 powder and carbon powder in a molar ratio of 1-5:1-5, where Me is a mixture of one or more of Hf, Zr, Ta, Ni, and Ti. Place the powder mixture and zirconia grinding balls in a corundum ball mill at a ball-to-powder ratio of 2:1. Add anhydrous ethanol as a milling medium to the powder at a mass ratio of 2-3:1. Seal the corundum ball mill and mill using a planetary ball mill at 200-500 rpm. After milling for 4-6 hours, pour the powder solution into a beaker and dry it in an electric forced-air drying oven at 60-100°C for 8-18 hours. Grind the dried powder in an agate mortar for 20-40 minutes to obtain a thoroughly mixed powder mixture.

[0041] Step 2: Pour the powder mixture into a tabletting mold with a diameter of Φ10 to Φ30 mm, and use a cold pressing process at a pressure of 4 to 15 MPa for 1 to 30 minutes to obtain a ceramic body with a diameter of Φ10 to Φ30 mm.

[0042] Step 3: Place a layer of graphite paper on the inner wall of the Al2O3 crucible, place the ceramic body into the alumina crucible, and then place the crucible in the center section of the tubular furnace for high-temperature heat treatment in a nitrogen environment. Before heating, nitrogen is first passed through for purge operation to remove oxygen in the furnace and prevent the occurrence of side reactions. After the purge is completed, nitrogen is introduced, and the temperature in the furnace is raised to 1500-1800°C at a rate of 2-10°C / min. After keeping warm for 1-3 hours, it is cooled to 300°C at a rate of 2-10°C / min, and then cooled to room temperature with the furnace. The sample is taken out to obtain transition metal carbonitride-SiC x N y Composite ceramics.

[0043] The present invention is further described in detail with reference to the specific embodiments of the crucible below:

[0044] Example 1:

[0045] Step 1: Mix HfSi2 powder and carbon powder in a molar ratio of 1:1, place the powder mixture and zirconia grinding balls into a corundum ball mill, where the ball-to-material ratio is 2:1, add anhydrous ethanol as a ball milling medium into the ball mill, and its mass ratio to the powder is 3:1. Then seal the corundum ball mill and use a planetary ball mill to mill at a speed of 400 rpm. After ball milling for 4 hours, pour the powder solution into a beaker and place it in an electric blast drying oven at a temperature of 70°C to dry for 15 hours. The dried powder is further ground with an agate mortar for 20 minutes to obtain a fully mixed powder mixture.

[0046] Step 2: Pour the powder mixture into a tabletting mold with a diameter of 10 mm, and use a cold pressing process at a pressure of 12 MPa for 10 minutes to obtain a ceramic body with a diameter of 10 mm.

[0047] Step 3: Place a layer of graphite paper on the inner wall of the Al2O3 crucible, place the ceramic body into the alumina crucible, and then place the crucible in the center of the tube furnace for high-temperature heat treatment in a nitrogen environment. Before heating, nitrogen is first passed through for purge operation to remove oxygen in the furnace and prevent the occurrence of side reactions. After the purge is completed, nitrogen is passed through, and the temperature in the furnace is raised to 1600℃ at a rate of 5℃ / min. After keeping warm for 2h, it is cooled to 300℃ at a rate of 4℃ / min, and then cooled to room temperature with the furnace. The sample is taken out to obtain HfC x N y -SiC x N y Composite ceramics.

[0048] The HfC prepared in this example x N y -SiC x N y Low-magnification SEM images of composite ceramics are shown in Figure 2. Figure 2 As shown, Figure 2 Analysis shows that the sample surface phase distribution is uniform. Combined with EDS energy spectrum element analysis and X-ray diffraction pattern analysis, such as Figure 3 and Figure 4 As shown, it can be seen that white HfC is formed on the surface of the sample x N y Crystalline and black amorphous SiC x N y In addition, Si-Hf-CN nanowires were formed on the sample surface. Therefore, it can be judged that HfC x N y -SiC x N y Composite ceramics.

[0049] Example 2:

[0050] Step 1: Mix HfSi2 powder and carbon powder in a molar ratio of 1:3, place the powder mixture and zirconia grinding balls in a corundum ball mill, where the ball-to-material ratio is 2:1, add anhydrous ethanol as a ball milling medium to the ball mill, and its mass ratio to the powder is 3:1. Then seal the corundum ball mill and use a planetary ball mill to mill at a speed of 400 rpm. After ball milling for 5 hours, pour the powder solution into a beaker and place it in an electric blast drying oven at a temperature of 70°C to dry for 17 hours. The dried powder is further ground with an agate mortar for 30 minutes to obtain a fully mixed powder mixture.

[0051] Step 2: Pour the powder mixture into a tabletting mold with a diameter of 10 mm, and use a cold pressing process at a pressure of 12 MPa for 10 minutes to obtain a ceramic body with a diameter of 10 mm.

[0052] Step 3: Place a layer of graphite paper on the inner wall of the Al2O3 crucible, place the ceramic body into the alumina crucible, and then place the crucible in the center of the tube furnace for high-temperature heat treatment under a nitrogen environment. Before heating, nitrogen is first passed through for purge operation to remove oxygen in the furnace and prevent the occurrence of side reactions. After the purge is completed, nitrogen is passed through, and the temperature in the furnace is raised to 1700℃ at a rate of 3℃ / min. After keeping warm for 2h, it is cooled to 300℃ at a rate of 4℃ / min, and then cooled to room temperature with the furnace. The sample is taken out to obtain HfC x N y -SiC x N yComposite ceramics.

[0053] According to the GJB-323A96 standard, the HfC prepared in this embodiment x N y -SiC x N y The composite ceramics were subjected to oxyacetylene torch ablation test at 2.4MW / m 2 After 60s of ablation under heat flux, a white oxide film is formed on the surface of the sample, such as Figure 5 As shown in the figure, it can be found that the oxide film on the surface of the sample after ablation is smooth and dense, without defects such as cracks.

[0054] Example 3:

[0055] Step 1: Mix HfSi2 powder and carbon powder in a molar ratio of 1:5, place the powder mixture and zirconia grinding balls in a corundum ball mill, where the ball-to-material ratio is 2:1, add anhydrous ethanol as a ball milling medium to the ball mill, and its mass ratio to the powder is 3:1. Then seal the corundum ball mill and use a planetary ball mill to mill at a speed of 400 rpm. After ball milling for 5 hours, pour the powder solution into a beaker and place it in an electric blast drying oven at a temperature of 70°C to dry for 17 hours. The dried powder is further ground with an agate mortar for 30 minutes to obtain a fully mixed powder mixture.

[0056] Step 2: Pour the powder mixture into a tabletting mold with a diameter of 10 mm, and use a cold pressing process at a pressure of 12 MPa for 10 minutes to obtain a ceramic body with a diameter of 10 mm.

[0057] Step 3: Place a layer of graphite paper on the inner wall of the Al2O3 crucible, place the ceramic body into the alumina crucible, and then place the crucible in the center of the tube furnace for high-temperature heat treatment in a nitrogen environment. Before heating, nitrogen is first passed through for purge operation to remove oxygen in the furnace and prevent the occurrence of side reactions. After the purge is completed, nitrogen is passed through, and the temperature in the furnace is raised to 1600°C at a rate of 4°C / min. After keeping warm for 2 hours, it is cooled to 300°C at a rate of 3°C / min, and then cooled to room temperature with the furnace. The sample is taken out to obtain HfC x N y -SiC x N y Composite ceramics.

[0058] The HfC prepared in this example x N y -SiC x N y The cross-section high-magnification SEM images of the composite ceramics were analyzed, such as Figure 6 As shown, it can be seen that white HfC is formed inside the sample x Ny phase, black SiC phase and black-gray SiC x N y Therefore, it can be judged that this embodiment obtains HfC x N y -SiC x N y Composite ceramics.

[0059] Example 4:

[0060] Step 1: Mix HfSi2 powder and carbon powder in a molar ratio of 1:2, place the powder mixture and zirconia grinding balls into a corundum ball mill, where the ball-to-material ratio is 2:1, add anhydrous ethanol as a ball milling medium into the ball mill, and its mass ratio to the powder is 2:1. Then seal the corundum ball mill and use a planetary ball mill to mill at a speed of 400 rpm. After ball milling for 5 hours, pour the powder solution into a beaker and place it in an electric blast drying oven at a temperature of 70°C to dry for 17 hours. The dried powder is further ground with an agate mortar for 30 minutes to obtain a fully mixed and uniform powder mixture.

[0061] Step 2: Pour the powder mixture into a tabletting mold with a diameter of Φ20 mm, and use a cold pressing process at a pressure of 14 MPa for 10 minutes to obtain a ceramic body with a diameter of 20 mm.

[0062] Step 3: Place a layer of graphite paper on the inner wall of the Al2O3 crucible, place the ceramic body into the alumina crucible, and then place the crucible in the center of the tube furnace for high-temperature heat treatment in a nitrogen environment. Before heating, nitrogen is first passed through for purge operation to remove oxygen in the furnace and prevent the occurrence of side reactions. After the purge is completed, nitrogen is passed through, and the temperature in the furnace is raised to 1500℃ at a rate of 3℃ / min. After keeping warm for 2.5h, it is cooled to 300℃ at a rate of 3℃ / min, and then cooled to room temperature with the furnace. The sample is taken out to obtain HfC x N y -SiC x N y Composite ceramics.

[0063] Embodiment 5:

[0064] Step 1: Mix ZrSi2 powder and carbon powder in a molar ratio of 1:3, place the powder mixture and zirconium oxide grinding balls into a corundum ball mill, where the ball-to-material ratio is 2:1, add anhydrous ethanol as a ball milling medium into the ball mill, and its mass ratio to the powder is 2:1. Then seal the corundum ball mill and use a planetary ball mill to mill at a speed of 400 rpm. After ball milling for 4 hours, pour the powder solution into a beaker and place it in an electric blast drying oven at a temperature of 70°C to dry for 15 hours. The dried powder is further ground with an agate mortar for 20 minutes to obtain a fully mixed and uniform powder mixture.

[0065] Step 2: Pour the powder mixture into a tabletting mold with a diameter of Φ20 mm, and use a cold pressing process at a pressure of 12 MPa for 10 minutes to obtain a ceramic body with a diameter of 20 mm.

[0066] Step 3: Place a layer of graphite paper on the inner wall of the Al2O3 crucible, place the ceramic body into the alumina crucible, and then place the crucible in the center of the tube furnace for high-temperature heat treatment under a nitrogen environment. Before heating, nitrogen is first passed through for purge operation to remove oxygen in the furnace to prevent the occurrence of side reactions. After the purge is completed, nitrogen is passed through, and the temperature in the furnace is raised to 1500℃ at a rate of 5℃ / min. After keeping the temperature for 2.5h, it is cooled to 300℃ at a rate of 4℃ / min, and then cooled to room temperature with the furnace. The sample is taken out to obtain ZrC x N y -SiC x N y Composite ceramics.

[0067] The present invention uses transition metal disilicide and C powder as raw materials, adopts nitriding heat treatment method, and generates transition metal carbonitride-SiC by high temperature reaction under nitrogen atmosphere. x N y (y can be 0) composite ceramics. High temperature reaction in nitrogen atmosphere can effectively prevent oxidation of raw materials during heating and ensure the stability of chemical composition and structure of the product. Nitrogen also participates in the formation of transition metal carbonitrides and SiC as one of the reactants. x N y Ceramic phase. During the preparation of transition metal carbonitride ceramics, SiC is generated simultaneously. x N y As the second phase, the ceramic phase can significantly improve the sintering performance. The presence of the second phase helps to promote the bonding between grains and improve the density and strength of the sintered body. x N yThe multiphase structure of composite ceramics gives them higher strength and toughness. The presence of the second phase can also disperse and absorb stress, prevent crack expansion, and thus improve the overall mechanical properties of the material. The interface formed between different phases in the composite ceramics can produce an interface effect, which helps to further improve the strength and toughness of the material. In addition, under high temperature conditions, transition metal carbonitride-SiC x N y Composite ceramics also exhibit excellent thermal stability and oxidation resistance. x N y Composite ceramics have broad application prospects in aerospace, energy, chemical industry and other fields.

[0068] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A transition metal carbonitride - SiC x N y The method for preparing a composite ceramic is characterized in that: include: The MeSi2 powder and carbon powder are mixed and ball-milled uniformly, and then further ground after drying to obtain a fully mixed powder mixture; Pressing the powder mixture into a ceramic body by cold pressing; The ceramic body is subjected to high temperature heat treatment in a nitrogen environment, and transition metal carbonitride-SiC is obtained after cooling. x N y Composite ceramics; In the MeSi2, Me is a transition metal; In the MeSi2, Me is a mixture of one or more phases of Hf, Zr, Ta, Ni, and Ti; The mixing molar ratio of the MeSi2 powder to the carbon powder is (1-5): (1-5); The high-temperature heat treatment has a heating rate of 2-10°C / min, a heat treatment temperature of 1500-1800°C, and a heat treatment time of 1-3 h.

2. A transition metal carbonitride-SiC according to claim 1 x N y The method for preparing a composite ceramic is characterized in that: During the ball milling process, the ball-to-material ratio is 2:1, the ball milling medium is anhydrous ethanol, and the mass ratio of the anhydrous ethanol to the mixed powder of MeSi2 powder and carbon powder is (2~3):

1.

3. A transition metal carbonitride-SiC according to claim 1 x N y The method for preparing a composite ceramic is characterized in that: During the ball milling process, the rotation speed is 200-500 rpm and the ball milling time is 4-6 h.

4. A transition metal carbonitride-SiC according to claim 1 x N y The method for preparing a composite ceramic is characterized in that: The drying temperature is 60-100° C., and the drying time is 8-18 h.

5. A transition metal carbonitride-SiC according to claim 1 x N y The method for preparing a composite ceramic is characterized in that: The cold pressing process comprises: The powder mixture is poured into a tablet pressing mold with a diameter of Φ10~Φ30 mm, and the pressure is maintained at 4~15 MPa for 1~30 minutes to obtain a ceramic green body with a diameter of Φ10~Φ30 mm.

6. A transition metal carbonitride-SiC according to claim 1 x N y The method for preparing a composite ceramic is characterized in that: The cooling process is as follows: cooling to 300°C at a rate of 2-10°C, and then cooling to room temperature.

7. Transition metal carbonitride-SiC prepared by the preparation method according to any one of claims 1 to 6 x N y Composite ceramics.

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