Carbon vacancies enhanced oxidation resistance of high-entropy carbides (Ti0.2V0.2Nb0.2Mo0.2W0.2)Cx

Abstract

High-entropy carbides have attracted considerable attention owing to their high melting point and excellent mechanical properties at high temperatures. However, exposures to high temperature environments are often accompanied by oxidation problems. Previous studies generally focused on improving oxidation properties by adding antioxidant elements. However, improving the oxidation properties intrinsically by modifying the crystal structure is still lacking. In this work, we innovative introduced tunable carbon vacancies into high-entropy carbides successfully.Consequently, the oxidation property of high-entropy carbides was improved, with the effect of carbon vacancies on the oxidation property was systematically investigated in this study. The (Ti0.2V0.2Nb0.2Mo0.2W0.2)Cx exhibits the best oxidation resistance property when x = 0.7, with the highest initial oxidation temperature and peak weight gain temperature (950.2 °C) and the lowest mass gain rate (25.2 %). This is mainly attributed to the formation of a higher number of carbonaceous oxides, which hinder the internal oxidation process.