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

摘要

Silicon carbide (SiC) is one of the attractive ceramics in respect of its excellent properties both in wear and thermal shock resistance. In this study, SiC coatings were fabricated by Plasma Spray-Vapor Deposition (PS-VD) process under very low pressure. Effect of plasma gas composition on the coating phase composition and microstructure was studied. The coatings were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the coatings deposited by Ar/H_2 plasma gas presented a composite phase of SiC and Si. Moreover, the content of Si in the coating increased with the increase of the hydrogen content in plasma gas. The deposition of silicon is possibly attributed to the reaction of C and hydrogen species in plasma jet. Thus, it was found that pure dense SiC coating can be obtained by using Ar/N_2 plasma gas.