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 1/3 Yb 1/3 Lu 1/3 ) 2 O 3 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 1/3 Yb 1/3 Lu 1/3 ) 2 O 3 -modified SiC ceramic exhibited better oxidation resistance than its individual oxides (Y 2 O 3 , Yb 2 O 3 , and Lu 2 O 3 ) modified SiC ceramic. The experimental and calculated results all indicate that the rare-earth atoms had the tendency to diffuse into the SiO 2 structure and occupy the interstitial positions within SiO 2 structure. The introduction of medium-entropy oxide (Y 1/3 Yb 1/3 Lu 1/3 ) 2 O 3 reduced the initial oxidation rate of the ceramic samples (1−3 h), and enhanced the stability of SiO 2 structure, thus resulting in a better oxidation resistance at 1700 °C.