Fretting wear and fracture behaviors of Cr-doped and non-doped DLC films deposited on Ti–6al–4V alloy by unbalanced magnetron sputtering

Cr-doped and non-doped diamond-like carbon (DLC) films were deposited on a Ti–6Al–4V alloy substrate using an unbalanced magnetron sputtering (UBMS). Fretting wear behavior of the specimens was investigated using a ball-on-disk fretting tester. The fracture phenomenon of the DLC films was determined as the number of fretting cycles to reach a high value of the friction coefficient. The results showed that the Cr-doped and non-doped DLC films exhibited a lower friction coefficient and wear rate compared to that of the uncoated specimen. However, the Cr-doped DLC film fractured only in a few cycles, while the non-doped DLC film fractured after fretting cycles of about 200,000. A fracture mechanism of the Cr-doped and non-doped DLC films was reported in this study.