Wei Yanbin, Ye Zhiyong, Wang Yalei, Xiong Xiang, Liu Zaidong, Wang Jinming, Li Tongqi
National Key Laboratory of Science and Technology on High-Strength Structural Materials, Central South University, Changsha 410083, China.
Aerospace Research Institute of Materials and Processing Technology, Beijing 100076, China.
Materials (Basel). 2024 Dec 21;17(24):6259. doi: 10.3390/ma17246259.
Carbon-fiber-reinforced carbon and silicon carbide (C/C-SiC) composites were prepared using chemical vapor infiltration (CVI) combined with reactive melt infiltration (RMI). The microstructure and flexural properties of C/C-SiC composites after oxidation in different temperature water vapor environments were studied. The results indicate that the difficulty of oxidation in water vapor can be ranked from easy to difficult in the following order: carbon fiber (CF), pyrolytic carbon (PyC), and ceramic phase. The surface CFs become cone-shaped under corrosion. PyC has a slower oxidation rate and lower degree of oxidation compared to CF. The SiO layer formed by the oxidation of SiC and residual Si was insufficient to fully cover the surface of CFs and PyC. As the temperature increased, the oxide film thickened, but the corrosion degree of CF and PyC intensified, and the flexural performance continuously deteriorated. The flexural strength of C/C-SiC composites was 271.86 MPa at room temperature. Their strength retention rates were all higher than 92.19% after water vapor corrosion at 1000 °C, still maintaining the "pseudoplastic" fracture characteristics. After water vapor corrosion at 1200 °C, the CFs inside the composites sustained more severe damage, with a strength retention rate as low as 48.75%. The fracture mode was also more inclined towards brittle fracture.
采用化学气相渗透（CVI）与反应熔体渗透（RMI）相结合的方法制备了碳纤维增强碳和碳化硅（C/C-SiC）复合材料。研究了C/C-SiC复合材料在不同温度水蒸气环境中氧化后的微观结构和弯曲性能。结果表明，水蒸气中氧化的难易程度由易到难依次为：碳纤维（CF）、热解碳（PyC）和陶瓷相。表面CFs在腐蚀作用下变成锥形。与CF相比，PyC的氧化速率较慢，氧化程度较低。SiC和残余Si氧化形成的SiO层不足以完全覆盖CFs和PyC的表面。随着温度升高，氧化膜增厚，但CF和PyC的腐蚀程度加剧，弯曲性能不断恶化。C/C-SiC复合材料室温下的弯曲强度为271.86MPa。在1000℃水蒸气腐蚀后，其强度保留率均高于92.19%，仍保持“假塑性”断裂特征。在1200℃水蒸气腐蚀后，复合材料内部的CFs遭受更严重的损伤，强度保留率低至48.75%。断裂模式也更倾向于脆性断裂。
