Silicon carbide composite cladding and preparation method therefor

Abstract

Disclosed in the present invention are a silicon carbide composite cladding and a preparation method therefor. The preparation method comprises: S1, providing a silicon carbide slurry; S2, enabling continuous silicon carbide fibers to pass through the silicon carbide slurry, so that the continuous silicon carbide fibers are impregnated with the silicon carbide slurry; S3, braiding the continuous silicon carbide fibers on the surface of an inner pipe to form a silicon carbide fiber braided layer; and S4, performing densification treatment on the silicon carbide fiber braided layer and an interface layer between the silicon carbide fiber braided layer and the inner pipe by means of chemical vapor infiltration. According to the preparation method for the silicon carbide composite cladding, the silicon carbide fiber braided layer impregnated with the silicon carbide slurry is composited on the outer surface of the inner pipe, and then densification treatment is carried out, to reduce pore defects in and between fiber bundles, improve the density, regulate the interface between the fiber and the inner pipe, and improve the toughness of the silicon carbide fiber braided layer, thereby obtaining a silicon carbide composite cladding having high strength, high thermal conductivity and high density.

Description

Silicon carbide composite cladding and preparation method thereof Technical Field

[0001] The present invention relates to the field of nuclear fuel technology, and in particular to a silicon carbide composite cladding and a preparation method thereof. Background Art

[0002] Currently, methods for preparing SiC cladding materials include NITE (Nano-Impregnation Transient Liquid Phase), CVI (Chemical Vapor Infiltration), PIP (Precursor Impregnation Pyrolysis), and RI (Reactive Infiltration). The NITE method requires demanding processes involving high temperatures (≥1750°C) and high pressures (≥10 MPa), making it unsuitable for preparing thin-walled SiC cladding materials with ultra-high aspect ratios. While the RI method can produce highly dense SiC cladding materials, residual Si present during the preparation process significantly reduces their high-temperature mechanical properties and corrosion resistance. While the PIP method can meet the requirements for preparing SiC thin-walled tubes, it typically requires multiple, lengthy impregnation-pyrolysis cycles and cannot address porosity issues within and between fiber bundles. While the CVI process simplifies the SiC composite cladding preparation process compared to the PIP process, the vapor infiltration process fails to fill pores within and between fiber bundles, resulting in a high porosity in the resulting SiC composite cladding.

[0003] Although SiC ceramic materials offer excellent intrinsic mechanical, thermal, corrosion, and radiation resistance properties, they contain numerous pore defects within SiC composite claddings. During service, the fiber-matrix interface is poorly bonded, preventing the composite fiber from achieving its desired reinforcement and toughening properties. This significantly reduces the material's toughness and reliability. The presence of pore thermal resistance also significantly reduces the cladding's thermal conductivity, hindering heat dissipation. Furthermore, pore defects significantly impact the cladding's corrosion and radiation resistance.

[0004] Based on the above analysis, it is necessary to propose a new method for preparing SiC composite cladding to obtain a SiC composite cladding with high density and good interface bonding layer. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a highly dense silicon carbide composite cladding with a good bonding interface and the prepared silicon carbide composite cladding.

[0006] The technical solution adopted by the present invention to solve the technical problem is: to provide a method for preparing a silicon carbide composite cladding, comprising the following steps:

[0007] S1. Providing silicon carbide slurry;

[0008] The silicon carbide slurry includes the following raw materials and their mass percentages: 10% to 45% silicon carbide mixed powder, 40% to 89.7% solvent, 0.1% to 5% dispersant, 0.1% to 5% plasticizer, and 0.1% to 5% defoaming agent;

[0009] S2, passing the silicon carbide continuous long fibers through the silicon carbide slurry, so that the silicon carbide continuous long fibers are impregnated with the silicon carbide slurry;

[0010] S3, weaving the silicon carbide continuous long fibers on the surface of the inner liner to form a silicon carbide fiber braided layer;

[0011] S4. Densification treatment is performed on the silicon carbide fiber braided layer and the interface layer between the silicon carbide fiber braided layer and the inner liner by chemical vapor infiltration to obtain a silicon carbide composite cladding.

[0012] Preferably, the silicon carbide mixed powder comprises silicon carbide whiskers and silicon carbide powder, and the mass percentage of the silicon carbide whiskers in the silicon carbide mixed powder is 10% to 50%.

[0013] Preferably, the diameter of the silicon carbide whisker is 0.01µm~10µm, and the aspect ratio of the silicon carbide whisker is 10~1000; the particle size of the silicon carbide powder is 0.1µm~10µm.

[0014] Preferably, the diameter of a single silicon carbide continuous long fiber is 5 μm to 20 μm.

[0015] Preferably, in step S3, the weaving method of the silicon carbide continuous long fibers on the surface of the inner liner pipe includes at least one of 2D weaving, 2.5D weaving and 3D weaving.

[0016] Preferably, in step S3, the cross angle of the braiding of the silicon carbide continuous long fibers is 10° to 90°.

[0017] Preferably, the material of the inner lining tube is selected from at least one of metal Zr, metal Nb, metal Ta, metal Mo, high entropy alloy, high entropy ceramic, and SiC.

[0018] Preferably, in step S4, the temperature of chemical vapor infiltration is 800° C. to 1300° C., and the time is 1 hour to 300 hours.

[0019] Preferably, in step S4, trichloromethylsilane is used as the reaction gas in chemical vapor infiltration;

[0020] Chemical vapor infiltration uses argon-hydrogen mixed gas as the protective gas, with a gas flow rate of 200ml / min ~3000ml / min and a gas pressure of 100Pa ~3000Pa.

[0021] Preferably, the method for preparing the silicon carbide composite cladding further comprises the following steps:

[0022] S5. Disposing a protective coating on the surface of the densified silicon carbide fiber braided layer.

[0023] Preferably, the protective coating includes at least one of a metal chromium layer and a high entropy alloy layer.

[0024] Preferably, the density of the silicon carbide composite cladding is 93% to 98%, and the cladding leakage rate is 1×10 -13 Pa·m 3 / s~1×10 -10 Pa·m 3 / s; The tensile strength of the silicon carbide composite cladding at room temperature is 250 MPa ~ 450 MPa, the tensile strength at a high temperature of 1200 ℃ is 300 MPa ~ 500 MPa, and the fracture toughness is 7 MPa m 1 / 2 ~30MPa·m 1 / 2 , thermal conductivity is 30W / (m·K)~80W / (m·K).

[0025] The present invention also provides a silicon carbide composite cladding, which is prepared by any of the above methods for preparing the silicon carbide composite cladding.

[0026] The beneficial effects of the present invention are as follows: a silicon carbide fiber braided layer impregnated with silicon carbide slurry is composited on the outer surface of the inner lining pipe, and then subjected to a densification treatment to reduce the hole defects within and between the fiber bundles, improve the density, regulate the interface between the fiber and the inner lining pipe, improve the toughness of the silicon carbide fiber braided layer, and obtain a silicon carbide composite cladding with high strength, high thermal conductivity and high density.

[0027] The preparation method of the present invention can realize the preparation of silicon carbide composite cladding tubes under low temperature (far below 2000°C) and no-load conditions; shorten the densification process cycle of the silicon carbide fiber braided layer, and realize the rapid preparation of silicon carbide composite cladding tubes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0029] FIG1 is a schematic diagram of a process for preparing a silicon carbide composite cladding according to an embodiment of the present invention;

[0030] FIG2 is a schematic diagram of the cross-sectional structure of a silicon carbide composite cladding according to an embodiment of the present invention;

[0031] FIG3 is a schematic diagram of the cross-sectional structure of a silicon carbide composite cladding according to another embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0033] The method for preparing the silicon carbide composite cladding of the present invention may include the following steps:

[0034] S1. Provide silicon carbide slurry.

[0035] The silicon carbide slurry includes raw materials and their mass percentages are as follows: 10% to 45% of silicon carbide mixed powder, 40% to 89.7% of solvent, 0.1% to 5% of dispersant, 0.1% to 5% of plasticizer, and 0.1% to 5% of defoaming agent.

[0036] The silicon carbide mixed powder includes silicon carbide whiskers and silicon carbide powder, with the mass percentage of silicon carbide whiskers in the silicon carbide mixed powder ranging from 10% to 50%. The diameter of the silicon carbide whiskers ranges from 0.01µm to 10µm, and the aspect ratio of the silicon carbide whiskers ranges from 10 to 1000. The particle size of the silicon carbide powder ranges from 0.1µm to 10µm.

[0037] The solvent is preferably anhydrous ethanol. The dispersant is at least one of oleic acid, stearic acid, and castor oil. The plasticizer is at least one of carboxymethyl cellulose, phenolic resin, and tetramethylammonium hydroxide. The defoamer is at least one of ethylene glycol, glycerin, and dimethyl silicone oil.

[0038] When preparing the silicon carbide slurry, all raw materials are mixed and stirred evenly, and the method used includes at least one of roller ball milling, planetary ball milling, magnetic stirring, and mechanical stirring.

[0039] S2. Passing the silicon carbide continuous long fibers through the silicon carbide slurry to impregnate the silicon carbide continuous long fibers with the silicon carbide slurry.

[0040] The silicon carbide continuous fibers are primarily passed through and impregnated with silicon carbide slurry in the form of fiber bundles, with each fiber bundle consisting of 100 to 1,000 silicon carbide continuous fibers. The diameter of a single silicon carbide continuous fiber ranges from 5µm to 20µm.

[0041] S3. Weaving silicon carbide continuous long fibers on the surface of the inner lining pipe to form a silicon carbide fiber braided layer.

[0042] In this step, the inner liner can be made of at least one material selected from metal Zr, metal Nb, metal Ta, metal Mo, high entropy alloy, high entropy ceramic, and SiC. The high entropy alloy comprises at least five metals selected from Zr, Ti, Nb, Ta, V, Cr, Mo, and W; the high entropy ceramic comprises carbides, nitrides, or silicides of at least five elements selected from Zr, Ti, Nb, Ta, V, Cr, Mo, and W, and may further comprise SiC.

[0043] When braiding continuous silicon carbide fibers onto the surface of the liner, the braiding angle is between 10° and 90°. Since the continuous silicon carbide fibers are primarily woven in bundles, the braiding angle is also the cross-angle between the bundles. The braided silicon carbide fiber layer can be single, double, triple, or more layers, or can include multiple layers, such as two or more of the following: single, double, triple, or more layers.

[0044] Furthermore, the weaving method of the silicon carbide continuous long fibers on the surface of the inner liner pipe includes at least one of 2D weaving, 2.5D weaving and 3D weaving.

[0045] In combination with the above steps S2 and S3 and Figure 1, in a preferred embodiment, a silicon carbide continuous long fiber bundle 17 that is not impregnated with slurry is released from a coil 18 and passed through a container 15 filled with silicon carbide slurry 16 to obtain a silicon carbide continuous long fiber bundle 13 impregnated with silicon carbide slurry. The silicon carbide continuous long fiber bundle 13 impregnated with silicon carbide slurry is woven on the outer surface of the inner liner 11 through a yarn guide 14 to form a tubular silicon carbide fiber braided layer 12 composited on the surface of the inner liner 11.

[0046] S4. Densification treatment is performed on the silicon carbide fiber braided layer and the interface layer between the silicon carbide fiber braided layer and the inner liner by chemical vapor infiltration to obtain a silicon carbide composite cladding.

[0047] The densification achieved through chemical phase penetration eliminates or reduces the holes in the fiber bundles or between the fiber bundles in the silicon carbide fiber braided layer, thereby improving the density of the silicon carbide fiber braided layer; at the same time, the interface bonding between the silicon carbide fiber braided layer and the inner liner is improved, thereby improving the toughness of the silicon carbide fiber braided layer.

[0048] Specifically, the temperature of the chemical vapor infiltration is 800° C. to 1300° C., and the time is 1 hour to 300 hours.

[0049] Chemical vapor infiltration uses trichloromethylsilane as the reaction gas and argon-hydrogen mixed gas as the shielding gas, with a gas flow rate of 200ml / min~3000ml / min and a gas pressure of 100 Pa~3000Pa.

[0050] Furthermore, according to actual needs, the method for preparing the silicon carbide composite cladding of the present invention may optionally include the following steps:

[0051] S5. A protective coating is provided on the surface of the densified silicon carbide fiber braided layer.

[0052] The purpose of the protective coating is mainly to prevent the silicon carbide from being dissolved in the silicon carbide composite cladding in the use environment.

[0053] The protective coating comprises at least one of a metal chromium layer and a high entropy alloy layer. The high entropy alloy of the high entropy alloy layer comprises at least five metals selected from the group consisting of Zr, Ti, Nb, Ta, V, Cr, Mo, and W.

[0054] In combination with the above preparation method, as shown in FIG2 , the silicon carbide composite cladding prepared by the present invention includes an inner liner tube 11 and a silicon carbide fiber braided layer 12 composited on the outer surface of the inner liner tube 11 in one embodiment.

[0055] In another embodiment, as shown in FIG3 , the silicon carbide composite cladding includes an inner liner tube 11 , a silicon carbide fiber braided layer 12 composited on the outer surface of the inner liner tube 11 , and a protective coating 20 disposed on the silicon carbide fiber braided layer 12 .

[0056] Furthermore, the density of the silicon carbide composite cladding of the present invention is 93% to 98%, and the cladding leakage rate is 1×10 -13 Pa·m 3 / s~1×10 -10 Pa·m 3 / s; the tensile strength of the silicon carbide composite cladding at room temperature is 250MPa~450MPa, the tensile strength at a high temperature of 1200℃ is 300MPa~500MPa, and the fracture toughness is 7MPa·m 1 / 2 ~30 MPa·m 1 / 2 , thermal conductivity is 30W / (m·K)~80W / (m·K).

[0057] The present invention will be further described below through specific examples.

[0058] Example 1:

[0059] A silicon carbide slurry was prepared using 29 wt% silicon carbide mixed powder, 70 wt% anhydrous ethanol solvent, 0.2 wt% dispersant, 0.3 wt% plasticizer, and 0.5 wt% defoamer as raw materials. The silicon carbide mixed powder contained 30 wt% silicon carbide whiskers, a diameter of 0.01 µm, an aspect ratio of 1000, and a particle size of 5 µm. The silicon carbide slurry was prepared by roller milling at 100 rpm for 24 hours.

[0060] The silicon carbide continuous fiber uses a single silicon carbide fiber with a diameter of 10 µm. The number of single fibers contained in the silicon carbide fiber bundle is 500. The silicon carbide fiber bundle, which has not been impregnated with the slurry, is passed through a slurry container filled with the above silicon carbide slurry. After the silicon carbide fiber bundle is impregnated with the silicon carbide slurry, the silicon carbide fiber bundle is obtained. The silicon carbide fiber bundle is woven onto the outer surface of the SiC liner tube through a yarn guide to form a single-layer 2D silicon carbide fiber braid. The cross-angle of the fiber bundle is 50 degrees. During the weaving process, the liner tube rotates clockwise or counterclockwise.

[0061] The silicon carbide fiber braid was densified using a chemical vapor infiltration (CVI) process. The CVI infiltration temperature was 1100°C, trichloromethylsilane was used as the reaction gas, and an argon-hydrogen mixture was used as the shielding gas. The gas flow rate was 200 ml / min, the gas pressure was 100 Pa, and the time was 100 hours. Silicon carbide coating was then applied to the rear surface of the CVI. The resulting silicon carbide composite cladding had a length of 4000 mm, a density of 96%, and a cladding leak rate of 1.0×10 -13 Pa·m 3 / s, its tensile strength is 450MPa at room temperature, its tensile strength at 1200℃ is 500MPa, and its fracture toughness is 30MPa·m 1 / 2 , thermal conductivity is 75 W / (m·K).

[0062] Example 2:

[0063] Silicon carbide slurry was prepared using 40.5wt% silicon carbide mixed powder, 59wt% anhydrous ethanol solvent, 0.15wt% dispersant, 0.2wt% plasticizer, and 0.15wt% defoamer as raw materials. In the silicon carbide mixed powder, the content of silicon carbide whiskers was 15wt%, the diameter of the silicon carbide whiskers was 0.1µm, the aspect ratio of the silicon carbide whiskers was 100, and the particle size of the silicon carbide powder was 10 µm.

[0064] The silicon carbide continuous long fiber uses a single silicon carbide fiber with a diameter of 15µm. The number of single fibers contained in the silicon carbide fiber bundle is 400. The silicon carbide fiber is woven into a double-layer 2D weave; the crossing angle of the fiber bundle weaving is 30°.

[0065] The SiC composite cladding was prepared by the method of Example 1. The CVI treatment temperature was 1200°C, trichloromethylsilane was used as the reaction gas, argon-hydrogen mixed gas was used as the protective gas, the gas flow rate was 600 ml / min, the gas pressure was 1000 Pa, and the penetration time was 50 h. The prepared SiC composite cladding had a length of 2000 mm, a density of 95%, and a cladding leakage rate of 1.0×10 -12 Pa·m 3 / s, its tensile strength is 350 MPa at room temperature, its tensile strength at 1200℃ is 400 MPa, and its fracture toughness is 25 MPa·m 1 / 2 , thermal conductivity is 40 W / (m·K).

[0066] Example 3:

[0067] Silicon carbide slurry was prepared using 10wt% silicon carbide mixed powder, 89.7wt% anhydrous ethanol solvent, 0.1wt% dispersant, 0.1wt% plasticizer, and 0.1wt% defoamer as raw materials. In the silicon carbide mixed powder, the content of silicon carbide whiskers was 50wt%, the diameter of the silicon carbide whiskers was 10µm, the aspect ratio of the silicon carbide whiskers was 10, and the particle size of the silicon carbide powder was 5µm.

[0068] The silicon carbide continuous long fiber uses a single silicon carbide fiber with a diameter of 20µm. The number of single fibers contained in the silicon carbide fiber bundle is 300. The silicon carbide fiber is woven into a double-layer 2.5D weave; the crossing angle of the fiber bundle weaving is 90°.

[0069] The SiC composite cladding was prepared by the method of Example 1. The CVI treatment temperature was 1300°C, trichloromethylsilane was used as the reaction gas, argon-hydrogen mixed gas was used as the protective gas, the gas flow rate was 3000 ml / min, the gas pressure was 3000 Pa, and the penetration time was 100 h. The prepared SiC composite cladding had a length of 3000 mm, a density of 96%, and a cladding leakage rate of 1.0×10 -11 Pa·m 3 / s, its tensile strength is 400MPa at room temperature, 450MPa at 1200℃, and its fracture toughness is 20MPa·m 1 / 2 , thermal conductivity is 35 W / (m·K).

[0070] Example 4:

[0071] Silicon carbide slurry was prepared using 45wt% silicon carbide mixed powder, 40wt% anhydrous ethanol solvent, 5wt% dispersant, 5wt% plasticizer, and 5wt% defoamer as raw materials. In the silicon carbide mixed powder, the content of silicon carbide whiskers was 10 wt%, the diameter of the silicon carbide whiskers was 0.01µm, the aspect ratio of the silicon carbide whiskers was 100, and the particle size of the silicon carbide powder was 5µm.

[0072] The diameter of a single silicon carbide fiber used in the silicon carbide continuous long fiber is 5µm. The number of single fibers contained in the silicon carbide fiber bundle is 1000. The silicon carbide fibers are woven into a three-layer 3D weave; the crossing angle of the fiber bundle weaving is 90°.

[0073] The SiC composite cladding was prepared by the method of Example 1. The CVI treatment temperature was 800°C, trichloromethylsilane was used as the reaction gas, argon-hydrogen mixed gas was used as the protective gas, the gas flow rate was 1000 ml / min, the gas pressure was 1000 Pa, and the penetration time was 100 h. The prepared SiC composite cladding had a length of 1000 mm, a density of 95%, and a cladding leakage rate of 1.0×10 -11 Pa·m 3 / s, its tensile strength is 350 MPa at room temperature, its tensile strength at 1200℃ is 400 MPa, and its fracture toughness is 30 MPa·m 1 / 2 , thermal conductivity is 30 W / (m·K).

[0074] Example 5:

[0075] Silicon carbide slurry was prepared using 35wt% silicon carbide mixed powder, 64.5wt% anhydrous ethanol solvent, 0.15wt% dispersant, 0.2wt% plasticizer, and 0.15wt% defoamer as raw materials. In the silicon carbide mixed powder, the content of silicon carbide whiskers was 30 wt%, the diameter of the silicon carbide whiskers was 0.1 µm, the aspect ratio of the silicon carbide whiskers was 100, and the particle size of the silicon carbide powder was 10 µm.

[0076] The diameter of a single silicon carbide fiber used in the silicon carbide continuous long fiber is 15 µm. The number of single fibers contained in the silicon carbide fiber bundle is 400. The silicon carbide fibers are woven into a single-layer 2D weave; the crossing angle of the fiber bundle weaving is 10°.

[0077] The SiC composite cladding was prepared by the method of Example 1. The CVI treatment temperature was 1300°C, trichloromethylsilane was used as the reaction gas, argon-hydrogen mixed gas was used as the protective gas, the gas flow rate was 400 ml / min, the gas pressure was 600 Pa, and the penetration time was 50 h. The prepared SiC composite cladding had a length of 2000 mm, a density of 98%, and a cladding leakage rate of 1.0×10 -13 Pa·m 3 / s, its tensile strength is 450MPa at room temperature, its tensile strength at 1200℃ is 500MPa, and its fracture toughness is 25MPa·m 1 / 2 , thermal conductivity is 30 W / (m·K).

[0078] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a silicon carbide composite cladding, characterized in that: The following steps are involved: S1. Providing silicon carbide slurry; The silicon carbide slurry includes raw materials and their mass percentages are as follows: 10% to 45% silicon carbide mixed powder, 40% to 89.7% solvent, 0.1% to 5% dispersant, 0.1% to 5% plasticizer, and 0.1% to 5% defoamer; S2, passing the silicon carbide continuous long fibers through the silicon carbide slurry, so that the silicon carbide continuous long fibers are impregnated with the silicon carbide slurry; S3, weaving the silicon carbide continuous long fibers on the surface of the inner liner to form a silicon carbide fiber braided layer; S4. Densification treatment is performed on the silicon carbide fiber braided layer and the interface layer between the silicon carbide fiber braided layer and the inner liner by chemical vapor infiltration to obtain a silicon carbide composite cladding.

2. The method for preparing the silicon carbide composite cladding according to claim 1, characterized in that: The silicon carbide mixed powder comprises silicon carbide whiskers and silicon carbide powder, and the mass percentage of the silicon carbide whiskers in the silicon carbide mixed powder is 10% to 50%.

3. The method for preparing the silicon carbide composite cladding according to claim 2, characterized in that: The diameter of the silicon carbide whisker is 0.01µm~10µm, and the aspect ratio of the silicon carbide whisker is 10~1000; the particle size of the silicon carbide powder is 0.1µm~10µm.

4. The method for preparing the silicon carbide composite cladding according to claim 1, characterized in that: The diameter of a single silicon carbide continuous long fiber is 5 µm to 20 µm.

5. The method for preparing the silicon carbide composite cladding according to claim 1, characterized in that: In step S3, the weaving method of the silicon carbide continuous long fibers on the surface of the inner liner pipe includes at least one of 2D weaving, 2.5D weaving and 3D weaving.

6. The method for preparing the silicon carbide composite cladding according to claim 1, characterized in that: In step S3, the cross angle of the braiding of the silicon carbide continuous long fibers is 10° to 90°.

7. The method for preparing the silicon carbide composite cladding according to claim 1, characterized in that: The material of the inner lining tube is selected from at least one of metal Zr, metal Nb, metal Ta, metal Mo, high entropy alloy, high entropy ceramic, and SiC.

8. The method for preparing the silicon carbide composite cladding according to claim 1, characterized in that: In step S4, the temperature of chemical vapor infiltration is 800° C. to 1300° C., and the time is 1 h to 300 h.

9. The method for preparing a silicon carbide composite cladding according to claim 1, characterized in that: In step S4, trichloromethylsilane is used as a reaction gas in chemical vapor infiltration; Chemical vapor infiltration uses argon-hydrogen mixed gas as the protective gas, with a gas flow rate of 200ml / min ~3000ml / min and a gas pressure of 100Pa~3000Pa.

10. The method for preparing a silicon carbide composite cladding according to any one of claims 1 to 9, characterized in that: The method for preparing the silicon carbide composite cladding further comprises the following steps: S5. Disposing a protective coating on the surface of the densified silicon carbide fiber braided layer.

11. The method for preparing a silicon carbide composite cladding according to claim 10, characterized in that: The protective coating includes at least one of a metal chromium layer and a high entropy alloy layer.

12. The method for preparing a silicon carbide composite cladding according to any one of claims 1 to 9, characterized in that: The density of the silicon carbide composite cladding is 93% to 98%, and the cladding leakage rate is 1×10 -13 Pa·m 3 / s~1×10 -10 Pa·m 3 / s; the tensile strength of the silicon carbide composite cladding at room temperature is 250MPa~450MPa, the tensile strength at a high temperature of 1200℃ is 300MPa~500MPa, and the fracture toughness is 7MPa·m 1 / 2 ~30MPa·m 1 / 2 , thermal conductivity is 30W / (m·K)~80W / (m·K).

13. A silicon carbide composite cladding, characterized in that: The silicon carbide composite cladding is prepared by the preparation method of any one of claims 1 to 12.

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