Abstract
Thermal barrier coating (TBC) is applied to high-temperature components of land-based gas turbine(GT). In TBC fabricated by thermal plasma process, a spallation damage is ofen observed in the components, because of subjecting to cyclic stress due to start-steady-stop operation of GT. Thus, it is necessary to grasp stress generated in the coating during service, in order to predict precisely life of the TBC spallation. The coating stress is composed of residual stress formed by thermal plasma process and thermo-mechanical stress generated during the operation. The residual stress is especially known to take different value with dependence on themal spray conditions (powder velocity and substrate temperature). This paper presents influence of the spray condition on the residual stress of TBC. Then, the residual stress evaluation method, which has been already proposed, is extended based on particle deposition process modeling thermal spray process. As obtained results, it was found that the residual stress measured by strain gage method increased compressively with higher particle velocity. Influence of substrate temperature on the residual stress was very few. The residual stress evaluation was extended in consideration of the elastic modulus changing by particle velocity. The results estimated by the extended method agreed with one measured by the strain gage method.
