Tribological properties of self-lubricating Ta-Cu films

摘要

Highlights•Lubricating phase Ta2O5formed on the worn surface of both Ta and TaCu films.•The tribological properties of TaCu film is superior to that of pure Ta film.•Cu addition increases the toughness of Ta film to avoid the generation of debris.AbstractIn this paper, Ta and TaCu films were deposited by using magnetron sputtering, and the tribological properties of the films against Si3N4balls were investigated under the loads of 2 N and 5 N. The average grain sizes of both films are below 25 nm. Ta and TaCu films have approximate hardness. While the wear rate of TaCu film is much smaller than that of Ta film. Post-wear testing XRD, Raman and XPS revealed the formation of tantalum oxide on the worn surface of both Ta and TaCu films. Tantalum oxidation is effectively lubricating to reduce friction coefficient. So the friction coefficient of both Ta and TaCu film is about 0.45 under different applied loads. Meanwhile, the addition of Cu could increase the toughness of the film, and avoid the generation of wear debris, resulting in a significant increase in wear resistance.