【摘要】 用因素分析法对C/SiC复合材料在氧气气氛下的氧化相对质量变化曲线进行了分析,确定了在不同温度区间内影响其相对质量变化的控制因素:在温度θ<700℃时复合材料的氧化速率由碳氧反应控制,属线性机制;随温度的升高,氧气通过涂层微裂纹的扩散将控制复合材料的氧化速率,属抛物线性机制;在温度θ>1000℃时,微裂纹逐步封闭,氧气通过SiO2生成层的扩散以及涂层表面的氧化将分别成为影响复合材料氧化速率的控制因素。在此基础上,建立了描述复合材料氧化过程的动力学模型。更多还原

【Abstract】 The mass change curves for C/SiC composites oxidized in dry oxygen were analyzed using factorization method and the different factors influencing the composites oxidation kinetics in different temperature ranges were determined, based on which a model for the oxidation kinetics of C/SiC composites was developed. The main conclusions are as follows: for θ<(700 ℃), the oxidation kinetics of the composites is controlled by the reaction rate of carbon with oxygen and so-called linear kinetics is observed; for 700 ℃<θ<1 000 ℃, it is the oxygen diffusion through coating cracks that controls the composites oxidation kinetics, representing a parabolic kinetics; for θ>1 000 ℃, the closing of coating cracks, oxygen diffusion through silica film and the oxidation of SiC coating will control the oxidation kinetics of the composites.更多还原