CVR法抗氧化处理对炭/炭复合材料氧化行为的影响

采用化学气相渗透 (CVI)炭和硅蒸汽与碳直接反应的化学气相反应法(CVR) 相结合,制备了针刺炭布C/C/SiC复合材料,研究了材料的氧化性能及氧化形貌。结果表明:制备的密度为2.47g/cm3、开孔率为2.2%的C/C/SiC材料经1160℃、65min氧化后,失重率仅为2.6%;而同结构C/C材料相同条件下失重率高达32%。但当所制备的材料密度较低 ( 1.81g/cm3)、开孔率较高 (7.1%) 时,由于其无法形成连续SiO₂保护膜,氧化从纤维与基体界面开始,表现出与C/C材料相类似的氧化过程。 

OXIDATION BEHAVIOR OF CARBON/CARBON COMPOSITE TREATED BY USING CHEMICAL VAPOR REACTION

Needled carbon cloth reinforced carbon/carbon (C/C) composite materials were improved by using the combination process of chemical vapor infiltration of carbon and direct reaction of silicon vapor with carbon at high temperature named as chemical vapor reaction (CVR) method to form SiC. Oxidation behavior of the obtained composites with various densities and open porosity was studied by static oxidation tests. The results show that, after being oxidated at 1160℃±10℃ for 65mins, the mass loss of the composites with a density of 2.47g/cm3 is less than 2.6%, while that of the same-structured C/C composite with a density of 1.95g/cm3 is as high as 32%. Treatment by CVR method can significantly improve the oxidation resistance properties. However, when the density of the C/C/SiC composite is lower and open porosity is higher, the effect is similar with C/C composite due to no formation of a continual layer of dense SiO2 on the specimen surface.