Lifetime prediction of plasma-sprayed thermal barrier coating systems

Relying on the statistical treatment of the morphological characteristics of the interface between yttria stabilized zicronia (YSZ) top coat (TC) and metallic bond coat (BC), finite element model of thermal barrier coating (TBC) is generated by a sinusoidal function. Meanwhile, considering the thermally grown oxide (TGO) growth, creep effects and top coating sintering, lifetime prediction methodology is proposed. Furthermore, stress development during thermal cycling is calculated by finite element method (FEM). Comparing the numerically predicted TBC stresses with the failure stress of top coating, the lifetime of plasma-sprayed (PS) TBC is predicted between 810 and 900 cycles, in agreement with experimental result of about 860 cycles, the average data of 8 specimen lifetimes. Different factors to the failure of TBC are compared.