High-temperature wear and oxidation behavior of (CrNbTaMoVW)N high entropy films deposited by reactive magnetron sputtering

Abstract

Rapid advancements in industrial technology necessitate mechanical parts capable of operating at high temperatures. High entropy alloy films have emerged as promising material for high-temperature resistant coatings, providing improved friction control and wear reduction. In this study, (CrNbTaMoVW)N high-entropy films were fabricated on YG6 cemented carbide substrates using reactive DC magnetron sputtering. The oxidation and tribological performance of the films were investigated across a temperature range from room temperature to 800 °C. Oxidation results revealed that (CrNbTaMoVW)N film maintained its simple Face-Centered Cubic (FCC) structure up to 600 °C for 3 h in the presence of air. At 800 °C, complete oxidation occurred, resulting in the formation of complex metal oxides and metal oxynitrides, and a structural transformation from FCC to these compounds. Following oxidation at 600 °C for 3 h, High-Entropy Alloy (HEA) film exhibited the maximum values of hardness (30.6 GPa) and modulus (301.7 GPa). Tribological results demonstrated an increase in both friction coefficient and wear rate with rising test temperature. However, (CrNbTaMoVW)N film showed a relatively low wear rate ranging from room temperature to 600 °C, approximately 10−15 m3/N•m, thus indicating excellent high-temperature tribological properties. Notably, the wear resistance of (CrNbTaMoVW)N film was significantly compromised at 800 °C due to the formation of loosely bonded metal oxides with reduced hardness, in contrast to the test temperature of 600 °C.