Effect of Plasma Spraying Power on Microstructure and High Temperature Oxidation Resistance of MoSi₂ Coating

MoSi2 coating on the surface of K403 nickel-base alloy was prepared by air plasma spraying using MoSi2 powders fabricated by self-propagating synthesis as spraying raw materials.The influence of plasma spraying power on microstructure and high temperature oxidation resistance of the MoSi2 coating was studied by XRD,SEM,EDS and high-temperature oxidation test.The results show that the coating was composed of three phases of MoSi2,Mo5Si3 and Mo.Phase composition of the coating was changed from rich-Si phase to rich-Mo phase with the increase of the plasma spraying power.The compact coating with MoSi2 main phase could be prepared by plasma spraying at 30 kW,which could obviously improve the high temperature oxidation resistance of the substrate.