Effect of the thermally grown oxide and interfacial roughness on stress distribution in environmental barrier coatings

Abstract

To clarify the role of interface morphology and thermally grown oxide (TGO) in the failure of environmental barrier coatings (EBCs). In this study, the effect of chemical expansion on free energy was considered based on the continuous thermodynamic framework. The effects of roughness and TGO growth on the stress distribution of EBCs were investigated. The results showed that the stress coupling effect led to the inhomogeneous growth of TGO by affecting the gas diffusion and gas inflow rate. The TGO thickness at the peak increased with increasing roughness, and the TGO thickness at the valley and the middle position decreased with increasing roughness. The y-direction at the TGO/EBC valley and the TGO/BC peak under tensile stress increased with the TGO thickness and roughness and may be the first to fail in delamination. The calculation results of the model can provide a theoretical basis for the coating design and manufacturing process.