论文部分内容阅读
用恒温热重法测定了表面经化学气相渗 SiC 的碳布层叠和碳毡抗氧化碳/碳复合材料在1300℃、空气中的氧化失重速率,并研究其高温氧化行为。氧化动力学测定结果表明,碳布层叠和碳毡抗氧化碳/碳材料在1300℃空气中1h 的平均氧化失重速率分别为0.024和0.033g/m~2·s。两种材料的氧化失重速率随氧化时间延长而减小。研究表明,材料表面 SiC 涂层中的微裂纹缺陷作为环境中氧的快速扩散通道,使得涂层底部基体的碳发生氧化。在达到稳态后,氧化速率限制过程为反应气体和产物气体通过 SiC 涂层底部气体边界层的扩散过程。
The rate of oxidation and weight loss of carbon cloth and carbon fiber reinforced carbon / carbon composite at 1300 ℃ in air were measured by thermo-gravimetric method and their high temperature oxidation behavior was studied. The results of oxidation kinetics showed that the average rate of weight loss of carbon cloth and carbon felt carbon monoxide / carbon material in air at 1300 ℃ for 1 hour were 0.024 and 0.033 g / m 2 · s, respectively. Oxidative weight loss rates of both materials decrease with increasing oxidation time. Studies have shown that the micro-crack defects in the SiC coating on the surface of the material act as a rapid diffusion channel for oxygen in the environment, causing the carbon in the substrate at the bottom of the coating to be oxidized. After the steady state is reached, the rate-limiting process is the diffusion of reactant gas and product gas through the gas boundary layer at the bottom of the SiC coating.