High temperature oxidation behavior of a EBPVD thermal barrier coating

A Y₂O₃ partially stabilized ZrO₂ ceramic top coating was deposited on a NiCrAlY bond coating by electron beam physical vapor deposition (EB-PVD). Isothermal oxidation was performed at 900 °G 1000 °G, and 1100 °C for 100 h, and thermal cyclic oxidation at 1050 °C. All the specimens were characterized by scanning electron microscopy (SEM), energy dispersion X-ray spectroscopy (EDS) and X-ray diffraction (XRD). It is shown that among the three isothermal oxidation conditions, the weight gain of the specimen at 1100 °C is the smallest in the initial 20 h. The thermal stress resulted from the thermal cycle and the growth stress of the oxide cause cracks at the interface between the Ni-Cr-Al-Y bond coating and its oxide, leading to failure of the EB-PVD thermal barrier coating.