Thermal cycling behaviour of lanthanum zirconate as EB-PVD thermal barrier coating

The thermal cycling behavior of Lanthanum Zirconate, La2Zr 2O7, for EB-PVD Thermal Barrier Coating (TBC), was investigated. TBCs have exhibited an increasing potential in improving the lifetime and efficiency of gas turbine engines by allowing an increase in turbine inlet temperatures. A complete delamination of lanthanum zirconate TBC was observed as a consequence of successive oxidation of the MCrAlY during the thermal cycling test. Cracking took place parallel to the surface and simultaneously the volume of the TGO and the stress in the interface TGO/La 2Zr2O7 was increased. The cracks grew in vertical direction to the TGO/MCrAlY interface resulting in oxidation attacks leading to a faster TGO growth. The TGO volume growth resulted in high intrinsic stress at the TGO/La2Zr2O7 interface and coating delamination. The results show that the pyrochloric lanthanum zirconate can be deposited as a TBC using a EB-PVD deposition process.