Oxidation behavior of (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C high-entropy ceramics at 1073-1473 K in air

The oxidation behavior of (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C high-entropy ceramics (HHC-1) was studied at 1073-1473 K in air for the first time. The results showed that the oxidation behavior of HHC-1 samples followed a parabolic rate law, in which the oxidation rate first increased with the temperatures increasing from 1073 to 1273 K and then decreased with the temperatures increasing from 1273 to 1473 K. In addition, except for the dense oxide layer formed at 1173 K, all the other oxide layers exhibit the laminated structure. These interesting results resulted from the formation of the different oxidation products.