Structure and Properties of Nonstoichiometric Y1-Nb O1.5+ for Thermal Barrier Coatings

Understanding the effect of nonstoichiometry on material properties is of critical importance for the Thermal Barrier Coatings (TBCs) application. In this work, the effect of nonstoichiometry was systematically investigated in Y3NbO7, a recently identified promising TBCs material for next-generation gas turbine engines. The results show that the nonstoichiometry effect mediates the microstructure, mechanical properties, thermophysical properties, oxygen ionic conductivity and optical transmittance. The results suggest that the oxygen ionic conductivity is correlated to the mass diffusion in the oxygen-deficient fluorite oxides Y1-xNbxO1.5+x. The stoichiometric composition Y3NbO7, with the lowest thermal conductivity and slowest mass diffusion in Y1-xNbxO1.5+x series, is optimal for the TBCs application, which can be of relevance for TBCs material design and coating fabrication.