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

In this work, silicon carbide coatings were fabricated by plasma spray-vapor deposition in order to study the effect of plasma gas mixtures on coating microstructure and phase composition. Coatings deposited by Ar-H₂ plasma gas were found to contain a composite phase of SiC and Si. Moreover, the content of Si increased with increasing H₂ content in the gas. The deposition of Si is possibly due to the reaction of C and hydrogen species in the plasma jet, which would explain why pure SiC coatings were obtained when Ar-N₂ gas was used.