Effects of Ce and Si additions to CoNiCrAlY bond coat materials on oxidation behavior and crack propagation of thermal barrier coatings

摘要

In thermal barrier coating (TBC) systems, thermally grown oxide (TGO) forms at the interface between the top coat and the bond coat (BC) during service. Delamination or spallation at the interface occurs by the TGO formation and growth. Therefore, modifications of the BC materials are one means to inhibit the TGO formation and to improve the crack resistance of TBCs. In this study, morphologies of TGO were controlled by using Ce and Si additions to conventional CoNiCrAlY BC material. The evaluation of the crack resistance was carried out using acoustic emission methods under pure bending conditions. As a result, when the BCs of TBCs with Ce added were aged at 1373 K over 10 h, the morphologies of the TGO were changed drastically. The BC materials of TBCs coated with Ce added indicated an improved crack resistance with high-temperature exposure. It is expected that the morphologies can improve the crack resistance of TBCs.