Oxidation behavior of medium-entropy (Y1/3Yb1/3Lu1/3)2O3 modified SiC ceramic at 1700 °C: Experimental and theoretical study

The medium-entropy oxide (Y_1/3Yb_1/3Lu_1/3)₂O₃ with a body-centered cubic structure was successfully synthesized by solid-state reaction process, and then it was introduced into SiC ceramic to study its effect on the oxidation behavior of SiC ceramic at 1700 °C. The (Y_1/3Yb_1/3Lu_1/3)₂O₃-modified SiC ceramic exhibited better oxidation resistance than its individual oxides (Y₂O₃, Yb₂O₃, and Lu₂O₃) modified SiC ceramic. The experimental and calculated results all indicate that the rare-earth atoms had the tendency to diffuse into the SiO₂ structure and occupy the interstitial positions within SiO₂ structure. The introduction of medium-entropy oxide (Y_1/3Yb_1/3Lu_1/3)₂O₃ reduced the initial oxidation rate of the ceramic samples (1?3 h), and enhanced the stability of SiO₂ structure, thus resulting in a better oxidation resistance at 1700 °C.