异形构件化学气相沉积SiC涂层的数值模拟

摘要

An integrated mathematical model depicting chemical vapor deposition (CVD) process of SiC coating on special-shaped components was developed.The model was proposed to simulate deposition behavior of SiC coating on typical spocial-shaped components.The calculated results indicate that the components with a slope have significant influence on the CVD process of SiC coating.Small angle between the slope and horizontal plant is beneficial to the quality control of CVD SiC.In terms of the components with step shape,it is suggested that the step part of a component should be placed along the downstream direction.The calculation results lay foundation on further research and optimization of CVD process of SiC coating.%根据化学气相沉积(CVD)工艺制备SiC陶瓷涂层的工艺特点和典型异形构件的结构特点,建立了异形构件表面化学气相沉积SiC涂层的数学模型.利用该模型,对CVD法在典型异形表面制备SiC涂层进行了数值计算和分析.计算结果显示,带有斜面的构件对CVD SiC沉积过程有显著影响,在反应器大小允许的情况下,构件放置时,斜面与水平面的夹角越小越好,并尽可能将构件长的一面与水平面平行,这样有利于沉积的涂层均匀.此外,对于带有台阶的构件来说,正放的构件表面浓度大于倒放的构件,而浓度梯度则小于倒放的构件.因此,在实际应用中,应尽量使台阶部分放在气流的下游.上述研究结果对CVD工艺制备SiC涂层的优化具有一定的指导意义.