Thermal Shock Resistance of Multiple Rare Earth Oxide Co-doped YSZ Thermal Barrier Coatings by EB-PVD
The Pt Al bond coat was firstly deposited on the DZ406 and DZ125 alloys by the electroplating Pt and vapor infiltration Al method,and then the 1.0Gd2O3-2.0Yb2O3 co-doped modified YSZ(GYb-YSZ)ceramic layer was prepared by electron beam physical vapor deposition(EB-PVD)method.The high temperature thermal shock performance of PtAl/GYb-YSZ thermal barrier coatings(TBCs)was investigated at 1250 ℃.The results show that the thermal shock life of DZ406 alloy+PtAl/GYb-YSZ TBCs is 10000 times,and that of DZ125 alloy+PtAl/GYb-YSZ TBCs is 7800 times.The coating failure mainly occurs at interface between the bond coat and the ceramic layer.During the thermal shock process,the thermally grown oxides(TGO)are formed and thickened by the oxidation of the bond coating,resulting in cracks initiation and propagation at interface between the bond coating and the ceramic layer,and eventually lead to coating spallation.The Hf element in the DZ125 alloy dif-fuses into the TGO,which destroys the integrity of the oxide film.The rapid growth and thickening of the oxide film lead to premature failure of the coating.
rare earththermal barrier coatingshigh temperature thermal shockthermally grown oxidespremature failure
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