ramic thermal barrier coatings (TBC) can exhibit premature in-service failure due to spallation as a consequence of exposure to elevated temperatures, aggressive environments, and cyclic loading. Lifetime assessment for TBC-systems requires methods for characterization damage accumulation that lead to spallation as a function of loading history. In this study controlled flaws were introduced into cylindrical TBC coated specimens by indentation. These controlled flaws were introduced in order to characterize interfacial fracture toughness of thermally cycled specimens and of specimens that underwent more realistic thermo-mechanical cycling with a thermal gradient across the coating. Indentation flaws introduced before testing were used to investigate the spallation phenomenon as a function of thermo-mechanical cycling.
Citation: Ceramic Engineering Science Proceedings
Pub Type: Journals
EB-PVD, indentation, interfacial fracture toughness, spallation, thermal barrier coatings, thermal gradient mechanical fatigue (TGM