Tribological performance and tribochemical processes in a DLC/steel system when lubricated in a fully formulated oil and base oil

► The a-C:15H coating durability is strongly oil dependant. ► Additive-derived tribofilms formed on the a-C:15H coating. ► Friction reduction is not significant using fully formulated (FF) oils. ► FF oils demonstrated a very good wear performance with the a-C:15H coating.