PREPARATION OF SiC COATING ON CARBON MATERIALS VIA CHEMICAL VAPOR REACTION

摘要

Carbon materials have been received much attention for high temperature structural applications because of their excellent properties of lightweight, high strength, high thermal stability and resistance to ablation [1]. However, their susceptibility of oxidation above 723 K limits their extensive applications as high temperature structural materials [2]. Therefore, the technology of reliable oxidation protection is crucial to exert their full potential. To solve this problem, much efforts have been carried out to explore new coating technologies and anti-oxidation coating systems, and it is generally considered that SiC is one of the most ideal coating materials due to its good mechanical properties, excellent anti-oxidation property and good physical-chemical compatibility with carbon materials [3]. Though SiC coating can be formed on carbon materials by several methods such as pack cementation [4], chemical vapor deposition (CVD) [5] and laser-induced chemical decomposition (LICD) [6], the single-layer coatings obtained by these methods usually possess a porous structure and may contain some defects (pores, pinholes or cracks). Therefore, it is essential and urgent to develop better methods that can prepare dense coatings with excellent oxidation resistance for carbon materials.