TBC delamination life prediction by stress-based delamination map

Abstract

The thermal barrier coating (TBC) is applied to gas turbine components to protect the hot-section components from extremely high temperature condition. Since metallic substrate cannot endure such severe condition of gas turbines, the delamination of the TBC can cause the failure of the whole system. Thus, the delamination life of the TBC is one of the most important issues for designing the hot-section components which operate at high temperature condition, and thermal stress between the coating layers is known as one of the major causes of the delamination. Especially, growth of thermally grown oxide (TGO) by Al-diffusion from bond coat is known as one of the main reasons to increase thermal stress between coating layers. Thus, in this study, the TGO growth behavior in the TBC is investigated, using the isothermally aged TBC specimens at high temperature conditions (900 - 1100°C), and thermal stress on TGO layer is investigated by finite element analysis, considering the TGO growth in the TBC. Finally, the test and FEA results are concluded as the TGO delamination map which can predict the delamination life time of TBC under isothermal condition.