Fretting wear behavior of DLC and diamond films: effects of amplitude and lubrication conditions

This study investigates the fretting wear behavior of diamond-like carbon (DLC) films deposited by plasma-based ion implantation (PBII) and filtered cathodic vacuum arc (FCVA) and that of diamond films deposited by plasma chemical vapor deposition (CVD) and diamond films treated by CF4 (tetrafluoromethane) plasma. The friction properties and surface structural changes of the DLC and diamond films are observed microscopically by varying vibration amplitudes and friction environments. Raman spectroscopy was used to analyze fretting wear behavior and failure mechanisms. The PBII-DLC and FCVA-DLC films showed an opposite dependence of friction behavior on amplitude due to their different indentation hardness and ID/IG values. However, only the friction of the PBII-DLC film can be improved under PAO lubrication conditions. Both CVD diamond and fluorinated diamond films showed good wear resistance under both dry and PAO conditions. In particular, the fluorinated diamond film surface exhibits microscopic changes under dry and PAO-lubricated conditions due to changes in the surface structure. Consequently, the fluorinated diamond film demonstrates minimal wear and a lower friction coefficient in response to small vibrations under both dry and PAO-lubricated conditions than the untreated diamond film.