Abstract
In this study, the damage process of Thermal Barrier Coatings (TBC) and Porous-TBC (P-TBC) exposed at high temperature under tensile loading was observed continuously, and the influence of exposure temperature on crack initiation strength and interface strength was clarified quantitatively. Yttria-stabilized zirconia for TBC and the mixed powder of yttria-stabilized zirconia and polyester for P-TBC as the top-coats was deposited by atmospheric plasma spray. Those specimens were exposed at high temperature in advance, and in-situ tensile test was conducted. It was found that crack propagated along the interface between top and bond coats in spite of room temperature test. Quantitative examination gave us that there is no great difference in crack initiation resistance between the exposed and as-sprayed specimens. However, the interfacial fracture toughness of the former was lower than that of the latter.
