Thermal cycling behavior and failure mechanism of La_2(Zr_(0.7)Ce_(0.3))_2O_7/ Eu~(3+)-doped 8YSZ thermal barrier coating prepared by atmospheric plasma spraying

摘要

Double-ceramic-layer (DCL) thermal barrier coatings (TBCs) of La_2(Zr_(0.7)Ce_(0.3))_2O_7 (LZ7C3) and Eu~(3+)-doped zirconia which was partially stabilized by 8 wt% yttria (8YSZ:Eu) was prepared by atmospheric plasma spraying. Thermal cycling behaviors of DCL coating were studied. The DCL coating shows a promising performance at 1250±50°C. The DCL coating spalled bit by bit from the top ceramic layer (LZ7C3) to the inner ceramic layer (8YSZ:Eu) during thermal cycling. The similar thermal expansions of LZ7C3 and 8YSZ prolonged the thermal cycling life of the coating. The sintering effect and phase transformation of LZ7C3, formation of the thermally grown oxide (TGO), and the sintering of 8YSZ:Eu, are the primary factors for the spallation of DCL coating.