致密SiC涂层的低压CVD成型工艺研究

Low Pressure CVD Formation Technology of Dense SiC Coating

为了改善碳材料的抗氧化性能,同时促进SiC涂层的工程化应用,本文采用低压CVD工艺沉积SiC涂层,研究致密SiC涂层的成型工艺。同时,对SiC涂层的沉积速率进行研究。实验结果表明:最佳的CVD沉积温度为1100℃,低温度促进SiC的定向生长,高温度使SiC产生气相沉积造成稀疏涂层。SiC涂层在石墨基体表面的沉积速率随温度的提高逐渐下降。混合气体比例(MTS∶H_(2)∶Ar)的增加促使SiC颗粒的尺寸逐渐减小,同时涂层的致密性也随之下降。此外,涂层的沉积速率先下降再上升。为获得致密的涂层,同时也要保证沉积速率,MTS流量应选择为10 sccm。

To improve the oxidation resistance of carbon materials and promote the engineering application of SiC coating,the low pressure CVD process was used to deposit SiC coating,and the forming process of dense SiC coating was studied.Meanwhile,the deposition rate of SiC coating was studied.The experimental results show that the optimal CVD deposition temperature is 1100℃,the low temperatures promote the directional growth of SiC,and the high temperatures cause the vapor deposition of SiC,resulting in sparse coating.The deposition rate of SiC coating on the surface of the graphite substrate gradually decreases with the increase of temperature.The increase of the mixture gas proportion(MTS:H_(2):Ar)promotes the gradual reduction of the size of SiC particles,meanwhile,the compactness of the coating also decreases.In addition,the deposition rate of the coating first decreases and then increases.To obtain a dense coating while maintaining deposition rates,the MTS flow rate should be selected as 10 seem.