Development of Surface Indentation Test Method for Evaluating TBC Property

Abstract

For ensuring a long-term reliability of thermal barrier coating (TBC) applied to gas turbine components, it is necessary to characterize the coating properties such as thermal conductivity and interfacial fracture toughness K_IFC by non-destructive evaluation method. In this study, we focused on surface indentation test to identify those coating properties. The results of the indentation test showed that the coating properties of as-sprayed TBC specimens could be identified by the slope of the loading-curve denoted as k1. In addition, the results implied that the decrease of K_IFC by a high-temperature exposure could be characterized by the maximum indentation depth h_max.