Thirty Years of Thermal Barrier Coatings (TBC), Photothermal and Thermographic Techniques: Best Practices and Lessons Learned

With the adoption of thermal barrier coatings (TBCs) to protect the hot parts of gas turbines at the end of the last century, the characterization of their thermophysical properties and the evaluation of their state of integrity has become necessary. That leads to the development and/or the adaptation of photothermal and thermographic techniques to meet the newly requirements that have emerged. Whereas this is not an all-encompassing review of all the literature on the subjects, this work summarizes the research and the development of techniques specifically aimed at measuring the thermophysical properties, the characterization of the microstructure and the identification of adhesion defects to the metal component of the TBCs. In the following, the best practices, the lessons learned, the successes and the defeats experienced along almost thirty years will be summarized.