Importance of surface oxide for the tribology of a Zr-based metallic glass

Thermally grown surface oxide layers dominate the single-asperity tribological behavior of a Zr 60 Cu 30 Al 10 glass. Increase in oxidation time leads to an increased contribution of shearing and a corresponding decreased contribution of ploughing to friction. This change in the dominating friction and wear mechanism results in an overall minor decrease of the friction coefficient of oxidized surfaces compared to the metallic glass sample with native surface oxide. Our results demonstrate the importance of creating a stable oxide layer for practical applications of metallic glasses in micro-devices involving sliding contact.