Comprehensive investigations on the influence of gun current of plasma spraying on the properties of silicon carbide films

Polycrystalline silicon carbide films have been prepared by the gas tunnel type plasma spraying method (GTPS). The effect of gun current on microstructure and mechanical properties was investigated. Scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy, nanoindentation and abrasive wear were used to characterize the structure, thickness, composition and the mechanical properties of SiC films. Microstructural studies revealed that the formation of cubic silicon carbide (C-SiC) at higher gun currents from 120 to 140 A. The SiC films have good-adhesion, dense, smooth and compact morphology. Hardness of SiC films strongly improved from 23 to 31.5 GPa as the gun current increased from 0 to 140 A. SiC films formed at higher gun current exhibits better wear resistance than that deposited at low gun current, mainly due to SiC films become more hard and more dense. The crystalline cubic silicon carbide films with good morphology and mechanical properties have been obtained from the GTPS method, which makes it a suitable material for high-temperature thermoelectric and mechanical applications.