Oxidation resistance of (Hf-Ta-Zr-Nb)C high entropy carbide powders compared with the component monocarbides and binary carbide powders

The non-isothermal oxidation behaviour of (Hf-Ta-Zr-Nb)C high entropy carbide (HEC4), component monocarbides (HfC, TaC, NbC, and ZrC), and (Hf-Ta)C binary carbide powders was compared and studied from room temperature to 1300°C using thermogravimetric analysis and differential scanning calorimetry. HEC4, with an increased oxidation onset temperature (OOT; 785°C) and intact particles, shows better oxidation resistance than the component monocarbides. Although (Hf-Ta)C has a higher OOT (860°C) than HEC4, the particles of (Hf-Ta)C disintegrate during oxidation, as did the monocarbides, while the HEC4 particles have greater structural stability.