Thermal oxidation description methodology of thermal barrier coatings on gas turbine blades considering service characteristics

Abstract

Predicting the thickness of Thermally Grown Oxide (TGO) and the residual stresses induced by TGO growth in the Thermal Barrier Coatings (TBCs) is significant work in analyzing the failure of TBCs. In practical applications, the operating temperature, oxygen partial pressure, aluminium content in TBCs, and porosity of the topcoat affect the oxidation rate. Therefore, a novel oxidation rate model is proposed to describe the effect of such factors. The parameters in the proposed model were fitted with isothermal degradation test data from prior literature. Then, a method for calculating the residual stress in a disk-shaped specimen was developed based on the oxidized growth strain model and the oxidized model. Finally, a variable-temperature oxidation experiment was performed to validate the new oxidation model. The average error between the predicted and experimental thicknesses is approximately 10%, and the average error between the residual stresses is 30%. Under the variable-temperature condition, the error between the predicted thickness and the average experimental thickness is 3.9%.