Evolution of microstructure, thermophysical and mechanical properties and wetting behavior of plasma-sprayed Yb2O3 and Y2O3 co-stabilized ZrO2 coatings during high-temperature exposure and CMAS corrosion

Abstract

Doping rare-earth elements has been regarded as one of the potential ways to enhance the comprehensive performance of thermal barrier coatings. In the study, the microstructure, thermophysical and mechanical properties, and wetting behavior of Yb2O3-Y2O3 co-stabilized ZrO2 (YbYSZ) were evaluated in detail as compared with Y2O3 stabilized ZrO2 (YSZ) counterpart. During high-temperature exposure and CMAS attack at 1300 °C × 32 h, the samples did not undergo phase transformation, while samples underwent phase transformation under CMAS corrosion. In the cross-section of CMAS penetration, YbYSZ penetration depth decreases by more than 20 % compared to YSZ, and the maximum degradation depth of YSZ and YbYSZ is 27.37 μm and 11.28 μm. Additionally, the thermal conductivity of YbYSZ is lower than that of YSZ. During high-temperature exposure, the hardness and elastic modulus of YSZ show a more significant upward trend than that of YbYSZ. During CMAS corrosion, the hardness and elastic modulus offer a downward trend, with YbYSZ value higher than that of YSZ. The samples were held at 1300 °C × 180 s, the contact angle difference between YSZ (59.2°) and YbYSZ (99.9°) is the largest. The YbYSZ coating exhibits better performance on resistibility to CMAS corrosion and high-temperature exposure.