A (Hf0.2Mo0.2Nb0.2Ta0.2Ti0.2)C system high-entropy ceramic with excellent mechanical and tribological properties prepared at low temperature

Abstract

It is a substantial challenge to prepare high-performance high-entropy carbides at low temperature. In this study, a system of (Hf0.2Mo0.2Nb0.2Ta0.2Ti0.2)C high-entropy ceramics with excellent mechanical and tribological properties were prepared at low temperature by using mixture with Aluminum. The results indicate that sintering temperature of specimen with 7 wt% Aluminum (HEC7A) can be reduced by 150 °C. Meanwhile, the synergy effect of the solid solution hardening and grain refinement enables the samples with a higher microhardness (≥18.1 GPa). Moreover, the addition of Aluminum can enhance the wear resistance. Especially for HEC7A at 900 °C, the wear rate is three times less than that of the pure sample. The primary anti-wear mechanism is the formation of Al2O3 tribo-films by the tribo-chemical reaction.