Abstract
It is well known that thermal spray condition affects the coating properties such as porosity, elastic modulus, coefficient of thermal expansion (CTE), coating fracture strength and coating cohesive strength. Therefore, residual stress formed in the sprayed coating and coating stress generated during in-service is dramatically changed with the thermal spray condition. In this study, effect of several kinds of thermal spray conditions on these properties of the coating was examined experimentally. Typical thermal barrier coating system composed of a partially stabilized zirconia (its chemical composition is 8wt%Y2O3-ZrO2) and CoNiCrAlY bond coating was selected herein. In-flight particle velocity and temperature, and the substrate temperature were changed as the thermal spraying process parameters varied. For the ceramic coating layer, the coating properties such as porosity, Vickers hardness, CTE, elastic modulus, bending fracture strength, fracture toughness of splat boundary and then coating residual stress were measured systematically.
