Life Prediction Model of Air Plasma Sprayed Thermal Barrier Coatings

A model was developed to predict the life of air plasma spraying thermal barrier coatings. The model was generated based on the stress distribution within the top coat as thermally grown oxide (TGO) grows. The effect of coefficient of thermal expansion (CTE), the thickness of TGO, and the radius of curvature of undulated TGO/top coat interface on the stress distribution was also investigated. The model parameter of calculating the life is fitted using an exponential formula rather than a constant value used in the existing models.  Moreover, particular attention was paid to the effect of roughness profile of the interface on the life of TBC system.  Using the proposed model, attempts are also made to study interactions between TGO, top coat and bond coat, which ultimately affect the life of TBCs.