Formation of rod-shaped wear debris and the graphitization tendency of Cu-doped hydrogenated diamond-like carbon films

Abstract

Diamond-like carbon (DLC) films have good lubrication properties, and the structure of wear debris or tribolayer at the friction interface affect the friction behavior of DLC films. In the present work, Cu-doped hydrogenated DLC (Cu-DLC:H) films with Cu contents of 3.19 at.%, 8.21 at.%, and 11.28 at.% were fabricated by a reactive high-power impulse magnetron sputtering. The formation of wear debris in the friction interfaces of Cu-DLC:H and the effects of Cu content on the tribological properties of the Cu-DLC:H films were investigated. The results show that Cu has uniform distribution in the Cu-DLC:H films with Cu contents of 3.19 at.% and 8.21 at.%. By contrast, for the Cu-DLC:H film with 11.28 at.% Cu, nanocrystalline Cu is surrounded by an amorphous carbon matrix. The wear resistance of the Cu-DLC:H films is better than that of the DLC:H film without Cu. Moreover, the wear debris of the Cu-DLC:H films on the friction interface is rod-shaped, and Cu accumulates in the debris, which can improve the graphitization of the wear debris on counterpart and further improve the wear resistance of the Cu-DLC:H films.