Analysis of wear behavior and graphitization of hydrogenated DLC under boundary lubricant with MoDTC

Diamond-like carbon (DLC) with high hardness and low friction has been applied to automotive parts. In this study, the significant wear of hydrogenated DLCs under molybdenum dithio-carbonate (MoDTC)-containing oil was evaluated by a reciprocating sliding tester and the wear has been investigated. Analysis of wear debris collected from oil after a sliding test revealed that DLC wear under MoDTC-containing boundary lubrication are caused by the graphitization, same as in solid lubrication confirmed by previous reports. On the other hand, Mo compounds that are decomposition products of MoDTC harden the surface of counterparts and have the potential of accelerated wear.