Design of thermal barrier coatings using gadolinium zirconate ceramics: A study on gadolinium zirconate/YSZ bilayers

FEM analysis and experiments are undertaken in this study for designing double ceramic-layered thermal barrier coatings (TBCs) to improve the resistance of coating layers to mechanical percussion. Double-coating layers, which comprise of a thermally insulating, Gd2Zr2O7-based layer upon a thermally adjustable, YSZ layer, are analyzed and designed with reference to indentation stress, and deposited by electron beam physical vapor deposition (EB-PVD). Additional analysis is also performed to find the optimal coating thickness. Linear elastic behaviors are assumed for the analysis, and the indentation stress-strain curves of the double-layer TBCs are compared with those of single-layer TBCs. The results from FEM analysis and experiments that use the Hertzian indentation technique indicate the advantage of double-layered TBCs for alleviating stress.