Microstructure and Properties of Silicon Carbide Coatings Prepared by Plasma Spray-Vapor Deposition

Silicon carbide (SiC) is one of the attractive ceramics in respect of its excellent properties both in wear and thermal shock resistance. In this research, SiC coatings were fabricated by PS-VD (Plasma Spray-Vapor Deposition) process under very low pressure to study the effect of plasma gas and substrate temperature on the coating compositions and microstructure. The coatings were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and micro hardness testing. The results show that spraying with Ar/H₂ plasma jet forms a coating containing silicon and the content of silicon in the coating increases with the increase of hydrogen content in plasma gas. Pure SiC coatings were deposited by using N₂ as secondary gas. Moreover, it was found that the deposition temperature influences deposition rate significantly and the deposition rate increases with the increase of deposition temperature. Furthermore, the effect of spray parameters on coating deposition behavior is also examined.