Failure Mechanism of Plasma Sprayed Physical Vapor Deposition (PS-PVD) Thermal Barrier Coating Under High Temperature and High Velocity Aviation Kerosene Gas Thermal Shock

The MCrAlY bottom layer and yttria-stabilized zirconia (YSZ) surface layer of thermal barrier coating were prepared on the surface of single crystal alloy blade by plasma sprayed physical vapor deposition (PS-PVD) method, and its failure mechanism under high temperature and high speed aviation kerosene gas thermal shock was analyzed by scanning electron microscope and energy dispersive spectrometer. The results showed that the YSZ surface layer had a columnar crystal structure, Under the thermal shock of high temperature and high speed aviation kerosene gas, a continuous thermally grown oxide film (TGO) was formed on the surface of MCrAlY bottom layer, and the thickness of TGO on the surface of MCrAlY bottom layer on the front of blade was obviously larger than that on the back of blade. In the area where the blade was directly impacted by the gas, the YSZ surface layer peeled off as a whole, column-like crystals broke from the root. In the area where the blade was not directly impacted by the gas, the YSZ surface layer was relatively complete. The overall peeling of YSZ surface layer was caused by entering of the particles in the external environment into the high-temperature and high-speed gas and eroding the thermal barrier coating.