The relation between the interface undulation and oxide film visco-elasticity in thermal barrier coatings

Interface undulation is one of the important mechanisms that are responsible for the damage and degradation of thermal barrier coatings. This work is aimed at analyzing the relation between the visco-elasticity of thermally grown oxide (TGO) and the interface undulation in thermal barrier coating system. A two-dimensional thermal barrier coating model was built for this reason, with the Fortran subroutines for the nonlinearity and anisotropy of TGO film integrated with the numerical model. Additionally, TGO growth stress is calculated from a three-dimensional theoretical model in order to show the further understanding of the interface undulation. It's revealed that the viscosity of TGO film is one decisive factor for the interface undulation. Like the decreasing TGO viscosity, the increasing TGO elasticity is able to promote the growth of the interface amplitude. Nonetheless, the elasticity of TGO film is not a source of the interface undulation.