Finite-element simulation of residual stress in zirconia thermal barrier coating

Thermal barrier coatings are used as thermal insulation and thermal protection for high-temperature components of aircraft engines. Service failure of the components is often caused by premature breaking of the coatings. The distributions of residual stress in a ZrO2/NiCoCrAlY thermal barrier coating during thermal cycling was here simulated using finite element method. Four kinds of models involving planar and curved interfaces between the bond and the ceramic top coat layers were established. The simulated results showed that the high residual stress which is about 100-300MPa is present at the interface between bond layer and ceramic layer. The residual stress in curved interface is larger than that in planar one, and concentrates mainly at the troughs. Structure for planar interface exhibits better than curved interface. The residual stress would increase obviously with the presence of thermally grown oxide layer.