Influence of input parameters on splat formation and coating thermal diffusivity in plasma spraying

The paper describes the relationship between the input parameters and the alumina coating properties in Plasma Spraying, such as porosity and thermal conductivity. The properties of plasma sprayed coatings, such as porosity, residual stress, and thermal conductivity depend on the coating microstructure, which is determined by the splat formation mechanism. Two experimental approach were used to investigate the influence of spray parameters on particle in-flight temperature and velocity. Optical micrographs of polished coating Cross-sections were used to determine the coating porosity using image analysis and point counting method. Thermal diffusivity of the coating was measured using laser flash method. The result shows that the increase of net energy increases the thermal diffusivity of coatings. Increase in particle in-flight characteristics resulted in splat morphology change from disk shaped to splashed, and improved splash interbounding and increase in splat contact area.