Preparation of MoSi_2-SiC-Si Coatings for C_f/SiC Composites by in situ Reaction Method

A MoSi2-SiC-Si coating was prepared by in situ reaction method.The phase composition and microstructure of the coating were studied by using XRD,SEM and EDS analysis,and then the anti-oxidation property of the coating was investigated.The results show that the thickness of obtained coating is about 120μm,and the main phases are composed of MoSi2,SiC and Si.The MoSi2-SiC-Si coating has excellent anti-oxidation property,which can protect Cf/SiC composites from oxidation at 1500℃ in air for 96h,the weight loss of the coated samples is only 1.8%.The weight loss of the coated Cf/SiC composites samples is primarily due to the reaction of Cf/SiC composites substrate and oxygen diffusing through the penetration cracks in the coating.