C / C-ZrC-SiC composite material with ZrO2 chopped fiber introduced on surface and preparation method and application thereof

Abstract

The invention belongs to the technical field of thermal protection of C / C composite materials, and relates to a C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface as well as a preparation method and application of the C / C-ZrC-SiC composite material. The composite material comprises a modified C / C composite material layer and a surface layer, the modified C / C composite material layer is composed of C / C, ZrC and SiC, and the surface layer is composed of ZrC, SiC, ZrO2 chopped fibers and ZrSi2. And sequentially laying the C / C composite material, the ZrSi2 powder and the mixed powder on the ZrSi2 powder, sealing, carrying out heat treatment at 1700-2000 DEG C, and cooling to room temperature to obtain the C / C-ZrC-SiC composite material with ZrO2 chopped fibers on the surface. The ZrO2 chopped fiber is used as a reinforcing phase, so that the compactness and integrity of an oxidation film formed in the ablation process of the modified C / C composite material are improved, and the modified C / C composite material shows more excellent ablation resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal protection of C / C composites, and particularly relates to a C / C-ZrC-SiC composite material with short-cut fibers introduced on the surface, and a preparation method and application thereof. 2 Background Art

[0002] C / C composite materials are a pure carbon structure composed of carbon fibers or their fabrics as reinforcements and pyrolytic carbon by chemical vapor infiltration or resin carbon and pitch carbon by liquid phase impregnation-carbonization as matrices. Due to their low density, high specific strength, high specific modulus, excellent ablation resistance, thermal shock resistance, low thermal expansion coefficient, and the characteristic that the strength increases instead of decreasing with the increase of temperature, C / C composite materials are widely used in components such as rocket engine nozzles and throat liners, nose cones of space shuttles and high-speed aircraft, and leading edges of wings. However, C / C composite materials have high oxidation sensitivity and oxidize in an aerobic environment above 370 °C. Oxidation damages the matrix, fibers, and the interface between the matrix and fibers of C / C composite materials, seriously affecting the mechanical properties of C / C composite materials under high-temperature harsh conditions, which limits their use in high-temperature aerobic environments.

[0003] Currently, the main methods for protecting C / C composite materials against oxidation ablation are coating technology and matrix modification technology. However, the challenge of mismatched thermal expansion coefficients between the matrix material and the coating material still exists. This will cause the accumulation of interfacial stress due to uneven thermal expansion of the coating and the matrix in a high-temperature environment, leading to coating cracking, peeling, and then material failure, which limits the application of coating technology in extreme environments. The matrix modification technology introduces high-temperature resistant and oxidation resistant ceramic phases (such as ZrC, SiC, etc.) into the interior of C / C composite materials to provide stable protection for the matrix.

[0004] The matrix modification technology mainly includes precursor infiltration technology (PIP), chemical vapor infiltration technology (CVI), reaction melt infiltration technology (RMI), etc. Among them, the reaction melt infiltration technology is widely used due to its advantages such as low cost, short cycle, and low residual porosity. However, the modified C / C composite materials obtained by reaction melt infiltration of C / C composite materials with traditional silicon-based high-temperature alloys (ZrSi 2 , HfSi 2 ) will form cracks and even spallation in the oxidation products under the action of thermal stress during the ablation process, which will reduce the protection ability of the oxide film and the ablation resistance of the material.

[0005] After retrieval, in Document 1: "Enhanced anti-ablation performance of carbon / carbon composites modified with ZrC-SiC", C / C-ZrC-SiC composites were prepared by the RMI method. After ablation for 55 s under the oxyacetylene flame test conditions with a heat flux density of 4.18 MW / m 2 the ZrO in the ablation center area 2 formed irregular aggregates through melting and recrystallization and connected into a porous skeleton. However, during the ablation process, the volatilization of gaseous products such as SiO and SiO 2 (g) and the volume expansion caused by the transformation of ZrO 2 from the tetragonal phase to the monoclinic phase during cooling led to cracks in the ablation center, which would accelerate the diffusion of oxygen into the matrix interior and was not conducive to improving the ablation performance of the modified C / C composites. Summary of the Invention

[0006] The purpose of the present invention is to provide a C / C-ZrC-SiC composite material with ZrO 2 short-cut fibers introduced on the surface, and its preparation method and application, so as to solve the problem that the bonding force of the oxide film formed during the ablation process of the C / C-ZrC-SiC composite material prepared by the existing reaction infiltration technology is insufficient, resulting in a reduction in its anti-ablation performance.

[0007] The present invention is realized through the following technical solutions: The present invention discloses a C / C-ZrC-SiC composite material with ZrO 2 short-cut fibers introduced on the surface, including a modified C / C composite material layer and a surface layer from bottom to top. The modified C / C composite material layer is composed of C / C, ZrC, and SiC, and the surface layer is composed of ZrC, SiC, ZrO 2 short-cut fibers, and ZrSi 2 composition.

[0008] Furthermore, the density and porosity of the C / C-ZrC-SiC composite material are 2.9 - 3.14 g / cm 3 and 14% - 16% respectively; When the C / C-ZrC-SiC composite material is ablated under an oxyacetylene flame with a heat flux density of 4.18 MW / m 2 for 40 s, the mass ablation rate and linear ablation rate after 40 s of ablation are -0.09~-1.78 mg / s and -4.13~-5.47 μm / s respectively.

[0009] The present invention also discloses a method for introducing ZrO 2Preparation method of C / C-ZrC-SiC composite material with short-cut fibers, comprising the following processes: Pre-treat the C / C composite material; Boil the C / C composite material obtained after pre-treatment, and dry the boiled C / C composite material; Mix ZrO 2 short-cut fiber powder and ZrSi 2 powder, and ball-mill to obtain a mixed powder; Place the C / C composite material parallel above the ZrSi 2 powder, add ZrSi 2 powder until the C / C composite material is completely covered by the ZrSi 2 powder and is higher than the upper surface of the C / C composite material, and then lay the mixed powder above the ZrSi 2 powder and seal it; Heat-treat at 1700 - 2000 °C for 0.5 - 3 h in an inert protective atmosphere and then cool to room temperature, grind, wash, and dry the obtained sample to obtain a C / C-ZrC-SiC composite material with ZrO 2 short-cut fibers on the surface.

[0010] Further, the pre-treatment of the C / C composite material is specifically: Grind, ultrasonically clean, and dry the C / C composite material.

[0011] Further, the ZrO 2 short-cut fiber powder and ZrSi 2 powder are mixed at a volume ratio of 1:(1 - 30).

[0012] Further, the step of placing the C / C composite material parallel above the ZrSi 2 powder, adding ZrSi 2 powder until the C / C composite material is completely covered by the ZrSi 2 powder and is higher than the upper surface of the C / C composite material, and then laying a layer of mixed powder above the ZrSi 2 powder and sealing it is specifically: Wrap the graphite paper around the bottom and the periphery of the graphite crucible, lay a layer of ZrSi 2 powder on the graphite paper at the bottom of the graphite crucible, and the thickness of the ZrSi 2 powder is 5 - 20 mm; Place the C / C composite material parallel on the ZrSi 2 powder, and then add ZrSi 2 powder until the C / C composite material is completely covered by the ZrSi 2The powder completely covers and is 5 - 10 mm higher than the upper surface of the C / C composite material; Then on ZrSi 2 Lay a layer of mixed powder on top of the powder, and the thickness of the mixed powder is 5 - 10 mm.

[0013] Furthermore, ZrO 2 The aspect ratio of the chopped fiber powder is (100 - 200):1.

[0014] Furthermore, the boiling temperature is 250 - 350 °C and the boiling time is 2 - 6 h.

[0015] Furthermore, dry the C / C composite material after the boiling treatment, specifically: dry the C / C composite material after the boiling treatment in an oven at 50 - 80 °C for 4 - 6 h.

[0016] The present invention also discloses the application of the C / C - ZrC - SiC composite material with ZrO 2 chopped fibers introduced on the surface as an ablation - resistant material. After ablation of the C / C - ZrC - SiC composite material with ZrO 2 chopped fibers introduced on the surface, the surface of the ablated composite material is composed of ZrO 2 oxide film. In the ZrO 2 oxide film, there are ZrO 2 fibers in a rod - like structure; Rod - like ZrO 2 fibers and ZrO 2 oxide film form a framework structure.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention discloses a C / C - ZrC - SiC composite material with ZrO 2 chopped fibers introduced on the surface. The modified C / C composite material is composed of C / C, ZrC, and SiC, and its surface is composed of ZrC, SiC, ZrO 2 chopped fibers, and ZrSi 2 . By introducing ZrO 2 chopped fibers on the surface of the C / C - ZrC - SiC composite material, the ZrO 2 chopped fibers, as a reinforcing phase, improve the overall structural integrity of the composite material, significantly increase the density of its surface ceramic layer, and enhance its application potential in extreme environments.

[0018] ZrO 2The presence of chopped fibers effectively inhibits the crack propagation of the modified C / C composites during ablation, improves the density and integrity of the oxide film formed during the ablation of the modified C / C composites. The complete and dense oxide film can effectively isolate the penetration of oxygen and other oxidizing gases into the matrix, avoid direct contact between the oxidation atmosphere and the matrix material, and reduce the progress speed of the oxidation reaction, thereby delaying the ablation of the material. In addition, the chopped fibers can form a "skeleton structure" with the oxide film to improve the mechanical strength of the oxide film, making the oxide film not easy to peel off or pulverize under high-temperature ablation and gas flow erosion, maintaining the structural integrity of the material, significantly enhancing the erosion resistance of the material, and enabling the material to have a longer service life in a high-temperature gas flow environment. The oxide film formed by the modified C / C composites during ablation is the key to their ablation resistance performance, ZrO 2 The chopped fibers improve the barrier effect of the oxide film by enhancing the density and integrity of the oxide film, making the modified C / C composites exhibit more excellent ablation resistance.

[0019] The present invention discloses a preparation method of a C / C-ZrC-SiC composite material with ZrO 2 chopped fibers introduced on the surface. The C / C composites are pretreated to remove external impurities from the samples, and then boiled to further remove impurities in the internal pores of the samples; ZrSi 2 powder is used as the bottom layer, and the C / C composites are placed parallel above the ZrSi 2 powder. ZrSi 2 powder is added until the C / C composites are completely covered by the ZrSi 2 powder and are higher than the upper surface of the C / C composites. Then, a layer of mixed powder is spread above the ZrSi 2 powder. The ZrSi 2 powder separates the C / C composites from the mixed powder. While introducing ZrO 2 chopped fibers on the surface, it also avoids the reaction between the C / C composites and the ZrO 2 chopped fibers. The role of using reactive melt infiltration to modify the C / C composites is as follows: during the reactive melt infiltration process, the ZrSi 2 powder melts at a high temperature of 1700 - 2000 °C and infiltrates into the pores of the C / C matrix through capillary action to react with the C matrix to generate ZrC and SiC, forming a C / C-ZrC-SiC composite material to improve the ablation resistance of the C / C composites. There are ZrO 2 chopped fibers in the ZrC and residual ZrSi 2 alloy, and the ZrO 2 chopped fibers are introduced onto the surface of the C / C-ZrC-SiC composites through the RMI process.

[0020] Furthermore, ZrO 2Short-cut fiber powder and ZrSi 2 The powder materials are mixed at a volume ratio of 1:(1 - 30). The aim is to optimize the synergistic effect between the short-cut toughening effect and the ceramic phase strengthening effect generated after ZrSi infiltration. 2 Short-cut toughening effect and ZrSi 2 Synergistic effect of the ceramic phase strengthening effect generated after infiltration.

[0021] Furthermore, the purpose of boiling the C / C composite material is to measure its density and porosity. The boiling time and temperature are appropriate to ensure that moisture can fully penetrate into the open pores of the C / C composite material.

[0022] The present invention also discloses the application of the C / C-ZrC-SiC composite material as an anti-ablative material. After ablation of the C / C-ZrC-SiC composite material with short-cut fibers introduced on the surface, the surface of the ablated composite material is composed of a ZrO oxidation film. 2 After ablation of the C / C-ZrC-SiC composite material with short-cut fibers introduced on the surface, the surface of the ablated composite material is composed of a ZrO oxidation film. 2 In the ZrO oxidation film 2 There are ZrO fibers in the shape of rods in the oxidation film; the framework structure formed by the rod-shaped ZrO fibers and the ZrO oxidation film can improve the mechanical strength of the oxidation film layer, enhance the bonding force of the oxidation film during the ablation process of the C / C-ZrC-SiC composite material, make the oxidation film more stable under high-temperature ablation and gas flow erosion, not easy to peel off or pulverize, and improve the anti-ablative performance of the reaction infiltration modified C / C composite material. 2 Rod-shaped ZrO fibers 2 Fibers and ZrO 2 The framework structure formed by the fibers and the ZrO oxidation film can improve the mechanical strength of the oxidation film layer, enhance the bonding force of the oxidation film during the ablation process of the C / C-ZrC-SiC composite material, make the oxidation film more stable under high-temperature ablation and gas flow erosion, not easy to peel off or pulverize, and improve the anti-ablative performance of the reaction infiltration modified C / C composite material. Description of the drawings

[0023] Figure 1 Process flow chart for preparing the C / C-ZrC-SiC composite material with short-cut fibers on the surface according to the present invention; 2 Process flow chart for preparing the C / C-ZrC-SiC composite material with short-cut fibers on the surface according to the present invention; Figure 2 Scanning electron microscope image of the mixed powder used in the present invention; Figure 3 Surface scanning electron microscopic image of the C / C-ZrC-SiC composite material with short-cut fibers on the surface prepared by the reaction infiltration process of the present invention; 2 Surface scanning electron microscopic image of the C / C-ZrC-SiC composite material with short-cut fibers on the surface prepared by the reaction infiltration process of the present invention; Figure 4 Surface X-ray diffraction pattern of the C / C-ZrC-SiC composite material with short-cut fibers on the surface prepared by the reaction infiltration process of the present invention; 2 Surface X-ray diffraction pattern of the C / C-ZrC-SiC composite material with short-cut fibers on the surface prepared by the reaction infiltration process of the present invention; Figure 5 Macroscopic image of the surface of the C / C-ZrC-SiC composite material with short-cut fibers on the surface prepared by the reaction infiltration process of the present invention after ablation; 2 Macroscopic image of the surface of the C / C-ZrC-SiC composite material with short-cut fibers on the surface prepared by the reaction infiltration process of the present invention after ablation; Figure 6 Surface of the C / C-ZrC-SiC composite material with short-cut fibers on the surface prepared by the reaction infiltration process of the present invention2 Scanning electron micrograph of the surface of the C / C-ZrC-SiC composite with chopped fibers after ablation. Detailed implementation manners

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention, that is, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments.

[0025] The detailed description of the embodiments of the present invention provided in the following drawings is not intended to limit the scope of the present invention to be protected, but only represents a selected embodiment of the present invention. Based on the drawings and embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.

[0026] It should be noted that: the term "comprising", "including" or any other variant is intended to cover non-exclusive inclusion, so that a process, element, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to the process, element, method, article or device.

[0027] The features and performance of the present invention are further described in detail in conjunction with the following embodiments.

[0028] Embodiment 1 This embodiment discloses a method for preparing a C / C-ZrC-SiC composite with chopped fibers, comprising the following steps: 2 Step 1: Select a C / C composite with a density of 1.3 g / cm and process it into a size of Ф 30 mm × 5 mm, and polish it successively with 50-mesh, 800-mesh and 3000-mesh silicon carbide sandpapers. After ultrasonic cleaning the sample with deionized water for 3 h, take it out and place it in an oven at 80 °C for drying for 8 h for standby. 3 Step 2: Boil the C / C composite obtained in Step 1 above, with a boiling temperature of 250 °C and a boiling time of 6 h. Further remove the impurities in the internal pores of the sample, and dry the boiled C / C composite in an oven at 80 °C for 4 h.

[0029] Step 3: Mix ZrSi

[0030] powder with ZrO with an aspect ratio of about 100:1 2 2The chopped fiber powder materials are mixed at a volume ratio of 25:1. The mixed powder materials are poured into a ball milling tank, and the mixed powder materials are ball milled at a rotation speed of 100 r / min for 3 h by using a planetary ball mill. The mixed powder materials are sieved with a 300-mesh sieve and placed in an oven at 80 °C for drying for 4 h for standby.

[0031] Figure 2 This is the scanning electron microscope image of the mixed powder materials used in this example. The one presenting a curly linear structure is ZrO 2 chopped fiber, with a diameter of about 500 nm and a length of about 50 μm; the one presenting a granular structure is ZrSi 2 alloy particles. It can be seen from Figure 2 that after ball milling, the two powder materials are mixed evenly, and the particle size meets the requirements of infiltration.

[0032] Step 4: Place the graphite paper at the bottom of the graphite crucible and wrap it around the graphite crucible. Spread a layer of ZrSi 2 powder materials on the graphite paper at the bottom of the graphite crucible. The thickness of the ZrSi 2 powder materials is 15 mm; Place the C / C composite material parallelly above the ZrSi 2 powder materials, add ZrSi 2 powder materials until the C / C composite material is completely covered by the ZrSi 2 powder materials and is 8 mm higher than the upper surface of the C / C composite material. Then spread a layer of mixed powder materials above the ZrSi 2 powder materials and seal them. The thickness of the mixed powder materials is 5 mm.

[0033] Step 5: Modify the C / C composite material by using the reactive infiltration process: Place the packaged crucible in a high-temperature heat treatment furnace, heat-treat it for 3 h in an argon protection atmosphere at 1700 °C, and then cut off the power supply to cool down to obtain a C / C-ZrC-SiC composite material with ZrO 2 chopped fibers on the surface.

[0034] Figure 3 This is the surface scanning electron micrograph of the C / C-ZrC-SiC composite material with ZrO 2 chopped fibers prepared by the reactive infiltration process in this example. The black phase is SiC generated by the reaction of ZrSi 2 and C, and the white phase is ZrC generated by the reaction of ZrSi 2 and C and the unreacted residual ZrSi 2 alloy. It can be seen from Figure 3 that there is ZrO in the ZrC and the residual ZrSi 2 alloy 2Short-cut fibers indicate that in this embodiment, ZrO has been successfully introduced onto the surface of the C / C-ZrC-SiC composite material through the RMI process. 2 Short-cut fibers are introduced onto the surface of the C / C-ZrC-SiC composite material.

[0035] The surface XRD pattern of the composite material prepared by the reaction infiltration process in this embodiment is as Figure 4 shown. It can be seen from the surface XRD pattern that the surface of the prepared composite material mainly consists of ZrC, SiC, and ZrSi 2 phases. The surface of the ZrO 2 short-cut fibers is coated with ZrC and ZrSi 2 . This indicates that C / C-ZrC-SiC has been successfully prepared through the reaction infiltration process, and it also verifies that Figure 3 the substances appearing in the scanning electron microscope are ZrC, SiC, and ZrSi 2 .

[0036] The density and porosity of the C / C-ZrC-SiC composite material obtained in this embodiment are 2.9 g / cm 3 and 15% respectively, and the composite material has a high relative density. The C / C-ZrC-SiC composite material obtained in this embodiment is ablated under an oxyacetylene flame with a heat flux density of 4.18 MW / m 2 for 40 s. The mass ablation rate and linear ablation rate after 40 s of ablation are -1.78 mg / s and -5.22 μm / s respectively.

[0037] Figure 5 is the macroscopic image of the ablated C / C-ZrC-SiC composite material with ZrO 2 short-cut fibers on the surface prepared by the reaction infiltration process in this embodiment. It can be seen from Figure 5 that a complete oxide film has formed on the surface of the ablated sample, and there are no obvious cracks or erosion on the sample surface. This reduces the diffusion channels of oxidizing gases such as oxygen into the matrix, thereby protecting the carbon matrix from oxidation and improving the ablation resistance of the reaction infiltration modified C / C composite material.

[0038] Figure 6 is the surface scanning electron micrograph of the ablated C / C-ZrC-SiC composite material with ZrO 2 short-cut fibers on the surface prepared by the reaction infiltration process in this embodiment. The surface of the ablated composite material consists of a ZrO 2 oxide film. Rod-like ZrO 2 fibers exist in the ZrO 2 oxide film. The rod-like ZrO 2 fibers are formed by the growth and thickening of the short-cut fibers introduced during the reaction infiltration process during the ablation process. The rod-like ZrO 2 fibers in the ZrO2 The distribution in the oxide film is beneficial to inhibiting the crack propagation, reducing the cracking tendency of the oxide film, isolating the diffusion of oxidizing gases such as oxygen into the matrix, and thus protecting the carbon matrix from oxidation. In addition, the rod-shaped ZrO 2 fibers and ZrO 2 The "skeleton structure" formed by the oxide film can improve the mechanical strength of the oxide film layer, enhance the bonding force of the oxide film during the ablation process of the C / C-ZrC-SiC composite material, make the oxide film more stable under high-temperature ablation and gas flow scouring, not easy to peel off or pulverize, and improve the ablation resistance of the reaction infiltration modified C / C composite material.

[0039] Example Two This example discloses a preparation method of a C / C-ZrC-SiC composite material with short-cut fibers introduced on the surface, including the following steps: 2 Step 1: Select a C / C composite material with a density of 1.2 g / cm and process it into a size of Ф 30 mm × 5 mm. Grind and polish it successively with 50-mesh, 800-mesh, and 3000-mesh silicon carbide sandpapers. After ultrasonic cleaning the sample with deionized water for 3 h, take it out and place it in an oven at 80 °C for drying for 8 h for standby. 3

[0040] Step 2: Boil the C / C composite material obtained in Step 1 above to measure its dry weight and wet weight. The boiling temperature is 250 °C and the boiling time is 6 h. Further remove the impurities in the internal pores of the sample. Dry the boiled C / C composite material in an oven at 60 °C for 5 h.

[0041] Step 3: Mix ZrSi 2 powder and ZrO 2 short-cut fiber powder with an aspect ratio of about 100:1 according to a volume ratio of 9:1. Pour the mixed powder into a ball milling tank, and use a planetary ball mill to ball mill the mixed powder at a rotation speed of 100 r / min for 3 h. Sieve the mixed powder with a 300-mesh sieve and place it in an oven at 80 °C for drying for 4 h for standby.

[0042] Step 4: Place the graphite paper at the bottom of the graphite crucible and wrap it around the graphite crucible. Spread a layer of ZrSi 2 powder on the graphite paper at the bottom of the graphite crucible. The thickness of the ZrSi 2 powder is 20 mm; Place the C / C composite material parallel to the ZrSi 2 powder above, and add ZrSi 2 powder until the C / C composite material is covered by ZrSi 2 ​The powder completely covers and is 10 mm higher than the upper surface of the C / C composite material, and then ZrSi 2 A layer of mixed powder is spread on top of the powder and sealed. The thickness of the mixed powder is 10 mm.

[0043] Step 5: Modify the C / C composite material by reactive melt infiltration process. Place the packaged crucible in a high-temperature heat treatment furnace and heat-treat it for 2.5 h in an argon protection atmosphere at 1750 °C. Then cut off the power and cool down to obtain a C / C-ZrC-SiC composite material with ZrO 2 short-cut fibers on its surface.

[0044] The density and porosity of the C / C-ZrC-SiC composite material obtained in this example are 3.01 g / cm 3 and 14% respectively, and the composite material has a high density. Subject the C / C-ZrC-SiC composite material obtained in this example to ablation under an oxyacetylene flame with a heat flux density of 4.18 MW / m 2 for 40 s. The mass ablation rate and linear ablation rate after 40 s of ablation are -1.42 mg / s and -4.54 μm / s respectively.

[0045] Example 3 This example discloses a preparation method of a C / C-ZrC-SiC composite material with ZrO 2 short-cut fibers introduced on its surface, including the following steps: Step 1: Select a C / C composite material with a density of 1.1 g / cm 3 and process it into a size of Ф 30 mm × 5 mm. Grind and polish it successively with 50-mesh, 800-mesh, and 3000-mesh silicon carbide sandpapers. After ultrasonic cleaning the sample with deionized water for 3 h, take it out and dry it in an oven at 80 °C for 8 h for standby.

[0046] Step 2: Boil the C / C composite material obtained in Step 1 above. The boiling temperature is 300 °C and the boiling time is 4 h. Further remove the impurities in the internal pores of the sample, and dry the boiled C / C composite material in an oven at 70 °C for 4 h.

[0047] Step 3: Mix ZrSi 2 powder and ZrO 2 short-cut fiber powder with an aspect ratio of about 100:1 according to a volume ratio of 7:1. Pour the mixed powder into a ball milling tank, and use a planetary ball mill to ball mill the mixed powder at a rotation speed of 100 r / min for 3 h. Sieve the mixed powder with a 300-mesh sieve and dry it in an oven at 80 °C for 4 h for standby.

[0048] Step 4: Place the graphite paper at the bottom of the graphite crucible and wrap it around the graphite crucible. Lay a layer of ZrSi powder on the graphite paper at the bottom of the graphite crucible. 2 The thickness of the ZrSi powder is 5 mm. 2 Place the C / C composite material parallel to the ZrSi powder. Add ZrSi powder above the C / C composite material until the C / C composite material is completely covered by the ZrSi powder and is 10 mm higher than the upper surface of the C / C composite material. Then lay a layer of mixed powder above the ZrSi powder and seal it. The thickness of the mixed powder is 10 mm. 2 Place the C / C composite material parallel to the ZrSi powder. 2 Add ZrSi powder above the C / C composite material until the C / C composite material is completely covered by the ZrSi powder and is 10 mm higher than the upper surface of the C / C composite material. 2 Then lay a layer of mixed powder above the ZrSi powder and seal it. The thickness of the mixed powder is 10 mm. 2 The thickness of the ZrSi powder is 5 mm.

[0049] Step 5: Modify the C / C composite material by the reactive infiltration process. Place the packaged crucible in a high-temperature heat treatment furnace and heat-treat it for 2 h in an argon protection atmosphere at 1800 °C. Then cut off the power and cool down to obtain a C / C-ZrC-SiC composite material with ZrO short fibers on the surface. 2 The density and porosity of the C / C-ZrC-SiC composite material obtained in this example are 3.11 g / cm³ and 16% respectively, and the composite material has a high density. Ablate the C / C-ZrC-SiC composite material obtained in this example under an oxyacetylene flame with a heat flux density of 4.18 MW / m² for 40 s. The mass ablation rate and linear ablation rate after 40 s of ablation are -1.01 mg / s and -4.13 μm / s respectively.

[0050] The density and porosity of the C / C-ZrC-SiC composite material obtained in this example are 3.11 g / cm³ and 16% respectively, and the composite material has a high density. 3 Ablate the C / C-ZrC-SiC composite material obtained in this example under an oxyacetylene flame with a heat flux density of 4.18 MW / m² for 40 s. 2 The mass ablation rate and linear ablation rate after 40 s of ablation are -1.01 mg / s and -4.13 μm / s respectively.

[0051] Example 4 This example discloses a preparation method of a C / C-ZrC-SiC composite material with ZrO short fibers introduced on the surface, including the following steps: 2 Step 1: Select a C / C composite material with a density of 1.2 g / cm³ and process it into a size of Ф 30 mm × 5 mm. Grind it successively with 50-mesh, 800-mesh, and 3000-mesh silicon carbide sandpaper. After ultrasonic cleaning the sample with deionized water for 3 h, take it out and place it in an oven at 80 °C for drying for 8 h for standby. The density of the C / C composite material is 1.2 g / cm³. 3 Process it into a size of Ф 30 mm × 5 mm, successively use 50-mesh, 800-mesh, and 3000-mesh silicon carbide sandpaper for grinding treatment, and ultrasonically clean the sample with deionized water for 3 h, then take it out and place it in an oven at 80 °C for drying for 8 h for standby.

[0052] Step 2: Boil the C / C composite material obtained in Step 1 above to measure its dry weight and wet weight. The boiling temperature is 350 °C and the boiling time is 2 h. Further remove the impurities in the internal pores of the sample. Dry the boiled C / C composite material in an oven at 50 °C for 6 h.

[0053] Step 3: Mix ZrSi 2 powder with ZrO 2 short-cut fiber powder with an aspect ratio of approximately 100:1 in a volume ratio of 5:1. Pour the mixed powder into a ball mill jar, and use a planetary ball mill to ball mill the mixed powder at a rotation speed of 100 r / min for 3 h. Sieve the mixed powder through a 300-mesh sieve and place it in an oven at 80 °C for drying for 4 h for standby.

[0054] Step 4: Place the graphite paper at the bottom of the graphite crucible and wrap it around the graphite crucible. Spread a layer of ZrSi 2 powder on the graphite paper at the bottom of the graphite crucible. The thickness of the ZrSi 2 powder is 10 mm; Place the C / C composite parallel to the ZrSi 2 powder, add ZrSi 2 powder until the C / C composite is completely covered by the ZrSi 2 powder and is 8 mm higher than the upper surface of the C / C composite. Then spread a layer of mixed powder on the ZrSi 2 powder and seal it. The thickness of the mixed powder is 8 mm.

[0055] Step 5: Modify the C / C composite by the reactive infiltration process. Place the packaged crucible in a high-temperature heat treatment furnace, heat-treat it in an argon protection atmosphere at 2000 °C for 0.5 h, and then cut off the power and cool down to obtain a C / C-ZrC-SiC composite with ZrO 2 short-cut fibers on the surface.

[0056] The density and porosity of the C / C-ZrC-SiC composite obtained in this example are 3.14 g / cm 3 and 15% respectively, and the composite has a high density. Ablate the C / C-ZrC-SiC composite obtained in this example under an oxyacetylene flame with a heat flux density of 4.18 MW / m 2 for 40 s. The mass ablation rate and linear ablation rate after 40 s of ablation are -0.09 mg / s and -5.47 μm / s respectively.

[0057] A C / C-ZrC-SiC composite with ZrO 2 short-cut fibers introduced on the surface prepared by the present invention includes a modified C / C composite layer and a surface layer from bottom to top. The modified C / C composite layer is composed of C / C, ZrC, and SiC, and the surface layer is composed of ZrC, SiC, ZrO 2 short-cut fibers, and ZrSi 2 composition.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent substitutions can still be made to the specific embodiments of the present invention, and any modification or equivalent substitution that does not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface, characterized in that: It includes a modified C / C composite material layer and a surface layer from bottom to top, the modified C / C composite material layer is composed of C / C, ZrC and SiC, and the surface layer is composed of ZrC, SiC, ZrO2 chopped fibers and ZrSi2.

2. The C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface according to claim 1, characterized in that: The density and porosity of the C / C-ZrC-SiC composite material are 2.9-3.14 g / cm 3 and 14%-16%; The C / C-ZrC-SiC composite material was heated to a heat flux of 4.18 MW / m 2 The samples were ablated under oxyacetylene flame for 40 s. The mass ablation rate and linear ablation rate after 40 s of ablation were -0.09~-1.78 mg / s and -4.13~-5.47 μm / s, respectively.

3. The method for preparing a C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface according to claim 1 or 2, characterized in that: The process includes: Pre-treating C / C composite materials; The C / C composite material obtained after the pretreatment is boiled, and the boiled C / C composite material is dried; The ZrO2 chopped fiber powder and the ZrSi2 powder are mixed and ball-milled to obtain a mixed powder; Place C / C composite material parallel to ZrSi2 powder, add ZrSi2 powder until the C / C composite material is completely covered by ZrSi2 powder and is higher than the upper surface of the C / C composite material, and then lay mixed powder on top of ZrSi2 powder and seal it; After heat treatment at 1700-2000 ℃ for 0.5-3 h in an inert protective atmosphere and then cooling to room temperature, the obtained sample was polished, cleaned and dried to obtain a C / C-ZrC-SiC composite material with ZrO2 chopped fibers on the surface.

4. The method for preparing a C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface according to claim 3, characterized in that: The pretreatment of the C / C composite material is specifically as follows: The C / C composite material is polished, ultrasonically cleaned, and dried.

5. The method for preparing a C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface according to claim 3, characterized in that: The ZrO2 chopped fiber powder and the ZrSi2 powder are mixed in a volume ratio of 1: (1-30).

6. The method for preparing a C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface according to claim 3, characterized in that: The C / C composite material is placed parallel to the ZrSi2 powder, ZrSi2 powder is added until the C / C composite material is completely covered by the ZrSi2 powder and is higher than the upper surface of the C / C composite material, and then a layer of mixed powder is spread on the ZrSi2 powder and sealed, specifically: Wrap graphite paper around the bottom and sides of the graphite crucible, and spread a layer of ZrSi2 powder on the graphite paper at the bottom of the graphite crucible. The thickness of the ZrSi2 powder is 5-20 mm. Place the C / C composite material parallel to the ZrSi2 powder, and then add ZrSi2 powder until the C / C composite material is completely covered by the ZrSi2 powder and is 5-10 mm higher than the upper surface of the C / C composite material; Then spread a layer of mixed powder on top of the ZrSi2 powder, with a thickness of 5~10 mm.

7. The method for preparing a C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface according to claim 3, characterized in that: The aspect ratio of ZrO2 chopped fiber powder is (100~200):

1.

8. The method for preparing a C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface according to claim 3, characterized in that: The boiling temperature is 250~350 ℃ and the boiling time is 2~6 h.

9. The method for preparing a C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface according to claim 3, characterized in that: The C / C composite material after the boiling treatment is dried, specifically: the C / C composite material after the boiling treatment is dried in an oven at 50-80° C. for 4-6 h.

10. Use of a C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface as claimed in claim 1 or 2 as an anti-ablation material, characterized in that: After ablation of the C / C-ZrC-SiC composite material with ZrO2 chopped fibers introduced on the surface, the surface of the composite material after ablation is composed of ZrO2 oxide film, in which there are rod-like ZrO2 fibers; The rod-shaped ZrO2 fibers and the ZrO2 oxide film form a skeleton structure.

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