Improving Corrosion Resistance of Rare Earth Zirconates to Calcium–Magnesium–Alumina–Silicate Molten Salt Through High-Entropy Strategy

Abstract

The erosion caused by high-temperature calcium–magnesium–alumina–silicate (CMAS) has emerged as a critical impediment to the advancement of thermal barrier coating (TBC). In this study, a series of high-entropy rare earth zirconates, (La0.2Sm0.2Dy0.2Er0.2Gd0.2)2(Zr1−xCex)2O7 (x = 0, 0.2, 0.4, 0.5) were synthesized through a solid-phase reaction, and their corrosion behavior against CMAS was investigated. Our findings demonstrate that numerous rare earth elements impede element diffusion, facilitate the formation of a compact oxide layer, and effectively hinder CMAS infiltration. Furthermore, rare earth elements with larger ionic radii exhibit enhanced solubility in apatite, whereas those with smaller ionic radii are more readily soluble in ZrO2. In general, the utilization of the high-entropy strategy is an effective approach to significantly improving corrosion resistance against CMAS.