ZrO <sub>2</sub> ‐doped YTaO <sub>4</sub> as potential CMAS‐resistant materials for thermal barrier coatings application
Di Wu, Yao Yao, Xiao Shan, Huangyue Cai, Lingyue Hu, Xiaofeng Zhao
Abstract
Abstract In this contribution, the ZrO 2 ‐doped YTaO 4 (Zr x Y 0.5− x /2 Ta 0.5− x /2 O 2 ( 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 Gd 2 Zr 2 O 7 . After 50 h corrosion at 1300℃, the corrosion depth in ZrO 2 ‐doped YTaO 4 bulks is about 50–80 µm (for a 20 mg/cm 2 CMAS deposition) in contrast with ~140 µm in Gd 2 Zr 2 O 7 bulk. The CMAS corrosion mechanism of ZrO 2 ‐doped YTaO 4 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 ZrO 2 doping content on CMAS resistance of YTaO 4 is discussed. It is elucidated that ZrO 2 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 ZrO 2 can ensure the excellent short‐ and long‐term CMAS resistance, but heavy doping of ZrO 2 will degrade the long‐term CMAS resistance.