Gradient distribution high-entropy ceramic-sic modified c / c composite material and preparation method

Abstract

The application relates to a gradient distribution high-entropy ceramic-SiC modified C / C composite material and a preparation method. The heterogeneous ceramic double gradient modification of a center area, a transition area and an edge area is realized by controlling the inner diameter of a mold and the number of times of suction filtration. The center area and the transition area are subjected to different times of selected area suction filtration modification cycles. Due to the influence of capillary action, the ceramic in the edge area is obtained by the appropriate diffusion of the liquid precursor in the center area and the transition area to the periphery. On this basis, the SiC introduced into the whole sample will also fill the residual gradient holes in a gradient manner. The selected area suction filtration modification method combined with the precursor impregnation and pyrolysis method can adjust the types and contents of ceramics in different areas according to the service environment, and the performance of materials in different areas can be designed.

Description

TECHNICAL FIELD

[0001] The application belongs to gradient distribution modified C / C composite materials and preparation methods, and relates to a gradient distribution high-entropy ceramic-SiC modified C / C composite material and a preparation method thereof. 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C-SiC modified C / C composite material and a preparation method thereof. BACKGROUND

[0002] Carbon / carbon (C / C) composite materials are prone to oxidation in high-temperature oxygen-containing environments. Domestic and foreign researchers have improved the oxidation resistance / ablation resistance of C / C composite materials by introducing oxidation inhibitors or ablation-resistant components into the materials to modify the matrix. According to the special service environment requirements of components, higher content of ultra-high-temperature ceramics needs to be introduced into the ablation-resistant region of C / C composite materials, and ceramics with higher thermal conductivity and lower thermal expansion coefficient need to be introduced into the heat transfer region. Therefore, researchers have proposed a preparation technology of gradient-modified C / C composite materials on the basis of uniform modification technology.

[0003] CN115894039A reports a kind of partition modified special-shaped carbon fiber reinforced composite component and a preparation method thereof. The method immerses the top end of the component in a precursor solution and then improves the densification of the unimmersed area at the bottom end by depositing pyrolytic carbon, thereby obtaining a composite component with a gradient distribution of ceramic phase content from the top end to the bottom of the component. However, the shape and position of the immersion area are limited, and it is difficult to effectively control the modification of the specified area.

[0004] CN116120095A reports a method for preparing gradient ultra-high-temperature ceramic modified C / C composite materials by selective reaction infiltration. The method covers specific areas by changing the powder placement process during the reaction infiltration process to achieve selective modification. However, it is difficult to effectively control the ceramic content and introduction area by self-diffusion of the melt.

[0005] Document 1“Chang Y B, Sun W, Xiong X, Chen Z K, Wang Y L, Hao Z H, Xu Y L, Microstructure and ablation behaviors of a novel gradient C / C-ZrC-SiC composite fabricated by an improved reactive melt infiltration, Ceramics International, 42 (2016) 16906-16915” prepared a gradient C / C-ZrC-SiC composite material by reactive melt infiltration method, and the composite material showed excellent ablation performance due to its unique gradient structure. But the reactive melt infiltration method is easy to cause the high-temperature melt to erode the fiber, which causes damage to the fiber and destroys the mechanical properties of the composite material.

[0006] Document 2“He Q C, Li H J, Wang C C, Li T, Lu J H, Microstructure and ablation property of gradient ZrC-SiC modified C / C composites prepared by chemical liquid vapor deposition, Ceramics International, 45 (2019) 13283-13296” prepared a gradient ZrC-SiC modified C / C composite material by chemical liquid vapor deposition method, and the results showed that the gradient composite material had lower thermal expansion coefficient and higher thermal conductivity coefficient, and the ablation rate of the gradient distribution modified composite material was greatly reduced compared with that of the uniform distribution modified composite material, but the process would affect the uniformity of the density of the composite material due to the thermal gradient formed by the heating body, and the sample edge was easy to form crust, which was not conducive to the densification of the sample, thus leading to the generation of a large number of defects. SUMMARY

[0007] Technical problems to be solved

[0008] In order to avoid the shortcomings of the prior art, the application provides a gradient distribution high-entropy ceramic-SiC modified C / C composite material and a preparation method, solves the problems that the existing process is difficult to realize gradient modification of specific shape regions and specified positions, and modification components of specific regions are difficult to effectively control. By controlling the inner diameter of the mold and the number of times of suction filtration, heterogeneous ceramic double gradient modification of the center region, the transition region and the edge region is realized, the center region and the transition region are subjected to different times of selective suction filtration modification cycles, due to the influence of capillary action, the ceramic in the edge region is obtained by appropriately diffusing the liquid precursor in the center region and the transition region to the surrounding, and on this basis, the SiC introduced into the whole sample will also fill the residual gradient holes in a gradient manner. By using the selective suction filtration modification method combined with the precursor impregnation and pyrolysis method, the types and contents of ceramics in different regions can be adjusted according to the service environment, and the performance of the materials in different regions can be designed.

[0009] Technical scheme

[0010] A preparation method of a gradient distribution high-entropy ceramic-SiC modified C / C composite material, characterized in that the high-entropy ceramic is (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 ), and the preparation steps are as follows:

[0011] Step 1: A selective suction filtration device is used to introduce (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C liquid precursor into the low-density C / C center region, and the material is placed in an oven at 80-100 DEG C for drying for 10-20 h;

[0012] Step 1 is repeated for 3-5 times;

[0013] Step 2: The dried material is placed in a graphite crucible and placed in a heat treatment furnace, the furnace temperature is raised to 1700-2100 DEG C under Ar protection and heat preservation for 2-3 h, after heat preservation, the power is turned off, and the heat treatment furnace is naturally cooled;

[0014] Steps 1-2 are repeated for 4-7 times;

[0015] Step 3: The inner diameter of the mold of the selective suction filtration device is changed, steps 1 and 2 are repeated until the mass of the center region of the material increases by no more than 4%, that is, the introduction of different contents of ceramics in the center region, the transition region and the edge region is completed;

[0016] Step 4: The material completed in the above step is immersed in a polycarbosilane liquid precursor as a whole, placed in a vacuum box, and the vacuum degree inside the cavity is controlled to be ≤-0.07 MPa by using a vacuum pump. The equipment is kept in vacuum for 20-40 min; the sample is placed in an oven at 80-100℃ and dried for 10-20 h;

[0017] The steps 3-5 are repeated for 3-5 times;

[0018] Step 5: The dried material is placed in a canister and placed in a tube furnace. The furnace temperature is raised to 1300-1500℃ under Ar protection and kept for 2-3 h. After the heat treatment, the power is turned off and the furnace is naturally cooled;

[0019] Step 6: Steps 4 and 5 are repeated multiple times until the mass of the material increases by no more than 4%;

[0020] Step 7: The heterogeneous ceramic double-graded modified C / C composite material is densified and sealed by isothermal chemical vapor deposition process, and the preparation of(Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C-SiC modified C / C composite material is completed.

[0021] The mold inner diameter of the selective filtration device of step 1 is 7-12 mm, and the gradient distribution of ultra-high temperature ceramic in the material is controlled by changing the shape of the mold.

[0022] The mold inner diameter of the selective filtration device of step 3 is 17-22 mm, and the different ceramic content modification of the central zone, transition zone and edge zone is realized by the cooperation of the mold inner diameter and the number of impregnation.

[0023] The density of the low-density C / C of step 1 is 0.7-1.2 g / cm 3 .

[0024] The liquid precursor of step 1 and step 4 is a mixture of liquid ceramic precursor or solid precursor and organic solution.

[0025] The precursor contains a mixture of mononuclear and polynuclear carbide or boride precursors.

[0026] The mass fraction of the precursor is 15%-30%.

[0027] A gradient distribution high-entropy ceramic-SiC modified C / C composite material prepared by the method, characterized in that: the material has a gradient distribution of(Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta0.2 )C content gradually decreases from the center to the edge, and the SiC content increases.

[0028] The gradient distribution of the material thermal expansion coefficient utilizes the high thermal conductivity coefficient ceramic at the edge to timely guide the heat in the ablation process, reduces the heat accumulation on the surface of the material, weakens the thermal erosion in the ablation process, and is beneficial to relieving the thermal stress mismatch in the material in the ablation process.

[0029] The application of any one of the methods is characterized by: the design and preparation of the ultra-high temperature material according to the service environment, adjusting the ceramic type and content in different regions.

[0030] Beneficial effects

[0031] The application provides a gradient distribution high-entropy ceramic-SiC modified C / C composite material and a preparation method thereof. 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C-SiC modified C / C composite material. By designing the inner diameter of the mold and the impregnation times, different times of selective filtration modification cycles are performed on the center region and the transition region, and the ceramic at the edge region is diffused from the liquid precursor to the surrounding, and on this basis, the introduced SiC also fills the residual gradient pores in a gradient manner. The content of (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C gradually decreases from the center to the edge, and the SiC content increases. The gradient distribution of the thermal expansion coefficient relieves the thermal stress mismatch of the material in the ablation process, the ceramic with high thermal conductivity coefficient at the edge timely guides the heat in the ablation process, and reduces the heat accumulation on the surface of the sample. The present technology controls the gradient distribution of the ceramic content by changing the modification times of different regions, is more controllable, reasonably designs the distribution of the gradient composition ultra-high temperature ceramic, reduces the density of the modified C / C composite material, avoids the waste of the "excessive" ultra-high temperature ceramic in the region with relatively mild service environment, and reduces the preparation cost. The selective filtration modification method refines the grain size of the ceramic phase, increases the grain boundary, and improves the strain tolerance of the material. The present application can adjust the ceramic type and content in different regions according to the service environment, design the material performance suitable for different regions in special environments, and the research idea can also be popularized and applied to other carbon-based or ceramic-based composite materials, used for improving the special service environment adaptability and resistance of the ultra-high temperature material, and has good application prospect.

[0032] The present application has the following advantages:

[0033] 1. The whole process has low requirements for equipment, and the device and process used are simple.

[0034] 2. The present technology has controllability by changing the number of times of selective zone filtration modification in different regions to control the gradient distribution of ceramic components and content.

[0035] 3. In the selective zone filtration process in the present technology, the liquid precursor is pressed into the sample under the action of atmospheric pressure by using pressure difference, so that the liquid droplets are broken, and the size of the converted ceramic particles is small; while in the traditional precursor impregnation and pyrolysis method, the sample is soaked in the liquid precursor and impregnation is completed in the whole negative pressure environment, so that the liquid droplets entering the interior of the matrix are large, and the size of the converted ceramic particles is large. Therefore, the present technology can realize the grain refinement of the introduced ceramic phase, increase the grain boundary, and improve the strain tolerance of the material.

[0036] 4. As shown in the following table, the densities of different modified C / C composite materials are compared, and the gradient structure design greatly reduces the density of the modified C / C composite material, avoids the waste of "excessive" high-temperature ceramic in the relatively mild service environment, and reduces the preparation cost of the material.

[0037] 5. As shown in the following table, the porosities of different modified C / C composite materials are compared, and the introduction of SiC reduces the open porosity of the modified C / C composite material, which is beneficial to alleviate the problem of porous and non-dense ceramic phase of the modified C / C composite material, and to a certain extent, improves the densification degree of the modified C / C composite material.

[0038] BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The process flowchart of the present application

[0040] Figure 2 SEM photos and particle size statistics of modified C / C composite materials by introducing (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C by different methods: (a), (c) selective zone filtration modification method; (b), (d) precursor impregnation and pyrolysis method. By comparing the SEM photos, it can be seen that the ceramic particles in the sample prepared by the selective zone filtration modification method are smaller, while the ceramic particles in the sample prepared by the traditional precursor impregnation and pyrolysis method are larger.

[0041] Figure 3 Gradient distribution (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2C-SiC modified C / C composites from center to edge of the SEM photos, (a) to (f) are six regions selected equidistantly from the center to the edge of the sample for micro characterization, it can be found that from the center to the edge of the sample (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C peak ratio of the peak value of SiC gradually reduced.

[0042] Figure 4 for gradient distribution (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C-SiC modified C / C composites from center to edge of the SEM photos, (a) to (f) are six regions selected equidistantly from the center to the edge of the sample for micro characterization, it can be found that from the center to the edge of the sample (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C (white phase) gradually reduced, and the content of SiC (gray phase) gradually increased. DETAILED DESCRIPTION

[0043] The application will be further described in conjunction with examples, drawings:

[0044] Example 1

[0045] 1, using anhydrous ethanol ultrasonic cleaning size is Φ 28mm × 5mm, the density of ~ 1.1g / cm 3 of low density C / C, and placed in the oven at about 80℃ drying 7h.

[0046] 2, the mold inner diameter of the selected region filter device is set to 10mm, to the low density C / C center zone introduced mass fraction of 25% (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C liquid precursor, and placed in the oven at 80℃ drying 20h.

[0047] 3, repeat step 2 for 4 times, the dried material into the graphite crucible and placed in the heat treatment furnace, the furnace temperature is raised to 1900℃ under Ar protection and holding 2h, after holding off power, waiting for the heat treatment furnace natural cooling.

[0048] 4、Repeat steps 2 and 3 a total of 5 times, then set the die inner diameter of the selected area filtration device to 20 mm, introduce a mass fraction of 25% (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C liquid precursor into the center zone and transition zone of the sample, and place it in an oven at 80°C for 20 h.

[0049] 5、Repeat steps 4 a total of 4 times, then place the dried material in a graphite crucible and place it in a heat treatment furnace, raise the furnace temperature to 1900°C under Ar protection and maintain for 2 h, after the holding period is over, turn off the power and wait for the heat treatment furnace to naturally cool down.

[0050] 6、Repeat steps 4 and 5 multiple times until the mass gain of the center zone of the material is no more than 4%. That is, the densification of the center zone and the introduction of an appropriate amount of ceramic in the transition zone are completed.

[0051] 7、Submerge the sample that has completed the above steps in a mass fraction of 20% polycarbosilane solution, place it in a vacuum box, use a vacuum pump to control the internal vacuum of the cavity to -0.09 MPa, and keep the equipment in a vacuum for 30 min; place the sample in an oven at 80°C for 20 h.

[0052] 8、Repeat step 7 a total of 3 times, then place the dried material in a canister and place it in a tube furnace, raise the furnace temperature to 1500°C under Ar protection and maintain for 2 h, after the holding period is over, turn off the power and wait for the heat treatment furnace to naturally cool down.

[0053] 9、Repeat steps 7 and 8 multiple times until the mass gain of the material is no more than 4%.

[0054] 10、Place the modified C / C obtained in step 9 in a vacuum carbon tube vapor deposition furnace to deposit pyrolytic carbon for 30 h, use pyrolytic carbon to further densify and seal the pores, and complete the preparation of the gradient distribution (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C-SiC modified C / C composite material.

[0055] Example 2

[0056] 1、Use anhydrous ethanol to ultrasonically clean low-density C / C with a size of Φ28 mm x 5 mm and a density of ~1.1 g / cm 3 , and place it in an oven at about 80°C for 7 h.

[0057] 2、Set the die inner diameter of the selected area filtration device to 11 mm, introduce a mass fraction of 25% (Ti0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C liquid precursor, which is placed in an oven at 80°C for 20h.

[0058] 3. Repeat step 2 for 4 times, then put the dried material into a graphite crucible and place it in a heat treatment furnace, and raise the furnace temperature to 1900°C under Ar protection and keep it for 2h, then turn off the power and wait for the heat treatment furnace to cool down naturally.

[0059] 4. Repeat steps 2 and 3 for 6 times, then set the mold inner diameter of the selected zone filtration device to 21mm, and introduce a mass fraction of 25% (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C liquid precursor, which is placed in an oven at 80°C for 20h.

[0060] 5. Repeat step 4 for 4 times, then put the dried material into a graphite crucible and place it in a heat treatment furnace, and raise the furnace temperature to 1900°C under Ar protection and keep it for 2h, then turn off the power and wait for the heat treatment furnace to cool down naturally.

[0061] 6. Repeat steps 4 and 5 multiple times until the mass gain of the material in the central region is not more than 4%. That is, the densification of the central region and the introduction of appropriate ceramic in the transition region are completed.

[0062] 7. Immers the sample completed the above steps in a mass fraction of 20% polycarbosilane solution, place it in a vacuum box, and use a vacuum pump to control the internal vacuum degree of the cavity to-0.09MPa, and keep the equipment in vacuum for 30min; then place the sample in an oven at 80°C for 20h.

[0063] 8. Repeat step 7 for 3 times, then put the dried material into a canister and place it in a tube furnace, and raise the furnace temperature to 1500°C under Ar protection and keep it for 2h, then turn off the power and wait for the heat treatment furnace to cool down naturally.

[0064] 9. Repeat steps 7 and 8 multiple times until the mass gain of the material is not more than 4%.

[0065] 10. Put the modified C / C obtained in step 9 into a vacuum carbon tube vapor deposition furnace to deposit pyrolytic carbon for 20h, and use the pyrolytic carbon to further densify and seal the holes, and complete the gradient distribution (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2Preparation of C-SiC modified C / C composite.

[0066] Example 3

[0067] 1. Low density C / C with size of Φ30mm x 5mm and density of ~1.1g / cm3 was cleaned by anhydrous ethanol ultrasonic cleaning and placed in an oven at about 80℃ for 7h. 3

[0068] 2. The inner diameter of the mold of the selected zone filtration device was set to 12mm, and the low density C / C was introduced into the central zone with 25% (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C liquid precursor, and was placed in an oven at 80℃ for 20h.

[0069] 3. After repeating step 2 for 4 times, the dried material was placed in a graphite crucible and placed in a heat treatment furnace, and the furnace temperature was raised to 1900℃ under Ar protection and kept for 2h, and after the heat preservation was completed, the power was turned off, and the heat treatment furnace was naturally cooled.

[0070] 4. After repeating steps 2 and 3 for 7 times, the inner diameter of the mold of the selected zone filtration device was set to 22mm, and the low density C / C was introduced into the central zone and the transition zone with 25% (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C liquid precursor, and was placed in an oven at 80℃ for 20h.

[0071] 5. After repeating step 4 for 4 times, the dried material was placed in a graphite crucible and placed in a heat treatment furnace, and the furnace temperature was raised to 1900℃ under Ar protection and kept for 2h, and after the heat preservation was completed, the power was turned off, and the heat treatment furnace was naturally cooled.

[0072] 6. Steps 4 and 5 were repeated multiple times until the mass gain of the central zone of the material was not more than 4%. That is, the densification of the central zone and the introduction of appropriate amount of ceramic in the transition zone were completed.

[0073] 7. The sample completed the above steps was immersed in a polycarbosilane solution with a mass fraction of 20%, placed in a vacuum box, and the vacuum degree inside the cavity was controlled at -0.09MPa by using a vacuum pump. The equipment was kept in vacuum for 30min; and the sample was placed in an oven at 80℃ for 20h.

[0074] ​8、 Repeat step 7 for 3 times, then put the dried material into the canister and place it in the tube furnace, raise the furnace temperature to 1500℃ under Ar protection and keep it for 2h, turn off the power after the holding time, and wait for the heat treatment furnace to cool naturally.

[0075] 9、 Repeat steps 7 and 8 multiple times until the material mass gain is no more than 4%.

[0076] 10、 Put the modified C / C obtained in step 9 into a vacuum carbon tube vapor deposition furnace to deposit pyrolytic carbon for 25h, further densify and seal the pores using pyrolytic carbon, and complete the preparation of gradient (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C-SiC modified C / C composite material.

[0077] The present technology controls the gradient distribution of ceramic content by changing the number of modifications to different regions, is more controllable, reduces the density of modified C / C composite material by reasonably designing the distribution of gradient component ultra-high temperature ceramics, avoids the waste of "excess" ultra-high temperature ceramics in regions with relatively mild service environment, and reduces the preparation cost, refines the ceramic phase grains by selective filtration modification method, increases the grain boundaries, and improves the strain tolerance of the material. The present application can adjust the types and contents of ceramics in different regions according to the service environment, design material properties suitable for different regions in special environments, and the research idea can also be applied to other carbon-based or ceramic-based composites to improve the special service environment adaptability and resistance of ultra-high temperature materials, and has good application prospect.

Claims

1. A method for preparing a gradient distribution high-entropy ceramic-SiC modified C / C composite material, characterized by comprising the following steps: The high-entropy ceramic is (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C, prepared by the following steps: ​ Step 1: introduce (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C liquid precursor into the low-density C / C central zone using a selected zone filtration device, and dry in an oven at 80-100°C for 10-20h; Repeat step 1 for 3-5 times; Step 2: Put the dried material into a graphite crucible and place it in a heat treatment furnace, and raise the furnace temperature to 1700-2100℃ under Ar protection and keep it for 2-3h, turn off the power after the heat preservation is over, and wait for the heat treatment furnace to cool down naturally; Repeat steps 1-2 for 4-7 times; Step 3: Change the inner diameter of the mold of the selected area filtration device, repeat steps 1 and 2 until the mass gain of the center area of the material is not more than 4%, that is, the introduction of different ceramic contents in the center area, transition area and edge area is completed; Step 4: Put the material completed in the above steps into a vacuum tank and immerse it in a liquid polycarbosilane precursor, use a vacuum pump to control the vacuum degree inside the cavity to ≤-0.07MPa, and keep the equipment in a vacuum state for 20-40min; Put the sample in an oven at 80-100℃ and dry for 10-20h; Repeat steps 3-5 for 3-5 times; Step 5: Put the dried material into a square canister and place it in a tube furnace, and raise the furnace temperature to 1300-1500℃ under Ar protection and keep it for 2-3h, turn off the power after the heat preservation is over, and wait for the heat treatment furnace to cool down naturally; Step 6: Repeat steps 4 and 5 several times until the mass gain of the material is not more than 4%; Step 7: Densification and sealing of the heterogeneous ceramic bi-gradually modified C / C composite material by isothermal chemical vapor infiltration process, completing the gradient distribution (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 )C-SiC modified C / C composite material The inner diameter of the mold of the selected area filtration device in step 1 is 7-12mm, and the gradient distribution of ultra-high temperature ceramics in the material is controlled by changing the shape of the mold; The inner diameter of the mold of the selected area filtration device in step 3 is 17-22mm, and the different ceramic content modification of the center area, transition area and edge area is realized by the cooperation of the mold inner diameter and the number of immersion; The density of the step 1 low density C / C is 0.7-1.2 g / cm 3 ; The prepared material has a gradually reduced content of (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 SiC from the center to the edge. The liquid precursor in steps 1 and 4 is a liquid ceramic precursor or a mixture of a solid precursor and an organic solution.

2. The gradient distribution high-entropy ceramic-SiC modified C / C composite prepared by the method of claim 1, characterized in that: Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2 The content of (Ti, Zr, Hf, Nb, Ta)C gradually decreases from the center to the edge, and the content of SiC gradually increases. The specific gradient distribution is designed according to the corresponding service environment.

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