ZrO2‐doped YTaO4 as potential CMAS‐resistant materials for thermal barrier coatings application

Abstract

AbstractIn this contribution, the ZrO2‐doped YTaO4 (ZrxY0.5−x/2Ta0.5−x/2O2 (x = 0, 0.1, 0.2, 0.28)) are proposed as potential CMAS‐resistant materials for TBCs. The corrosion behavior of those materials under CMAS attack are investigated from thermodynamics and kinetics. The results show that all compositions have the much better CMAS resistance than the classical Gd2Zr2O7. After 50 h corrosion at 1300℃, the corrosion depth in ZrO2‐doped YTaO4 bulks is about 50–80 µm (for a 20 mg/cm2 CMAS deposition) in contrast with ~140 µm in Gd2Zr2O7 bulk. The CMAS corrosion mechanism of ZrO2‐doped YTaO4 is elucidated, and the excellent CMAS resistance is attributed to the rapid formation and followed thickening of dense reaction product layer. Furthermore, the effects of ZrO2 doping content on CMAS resistance of YTaO4 is discussed. It is elucidated that ZrO2 doping can inhibit the precipitation of apatite, decrease the consumption of CMAS melt, and change the morphology of dense reaction layer. In summary, minor doping of ZrO2 can ensure the excellent short‐ and long‐term CMAS resistance, but heavy doping of ZrO2 will degrade the long‐term CMAS resistance.