SiC纤维CVD涂层工艺研究

A Study of Preparation of Protecting Coating on SiC Filaments by CVD Process

对SiC纤维的CVD涂层工艺进行研究。实验发现采用BCl3,H2及CH4作为反应气体,采用与SiC纤维生产工艺相匹配的走丝速度并控制一定的工艺参数,在1350℃左右可得到厚度2～3mm且表面致密的B4C涂层,纤维涂层后性能基本保持不变。仅采用BCl3及CH4作为CVD涂层工艺反应气体,在1180-1250℃即可沉积出表面光滑致密,厚度2—3mm的富碳B4C涂层,涂层后纤维性能可提高10％左右,且涂层与纤维结合强度很高,优于B4C 涂层与SiC纤维的结合强度。实验还发现SiC纤维涂覆B4C及富碳B4C涂层后,能有效阻隔界面反应,可大幅提高 SiC／Ti基复合材料的性能。

The coating of SiC filament prepared by CVD process was investigated. Test indicated that dense B4C protective layer about 2 ~ 3μm thick could be coated on SiC surface at about 1350 ℃ by using a gas mixture of H2 + CH4 + BCl3 and controlling the filament takeup speed matching the deposition process of SiC. The tensile strength of B4C-coated SiC fibres were basically unchanged in optimal parameter. Meanwhile, dense and smooth B4C-C coating with thickness of 2 ~3μm was also deposited on SiC surface at 1180 - ...