E. I. Meletis, The University of Texas at Arlington, Arlington, TX; Y. Cheng, University of Texas at Arlington, Arlington, TX

Summary: Diamondlike carbon (DLC) films have been extensively studied in the past since they exhibit an attractive combination of properties including excellent tribological characteristics. Low friction has been attributed to a low shear strength graphite-like transfer layer forming at the sliding interface. We have been the first to provide direct TEM evidence of graphite formation in the transfer layer during wear and propose a wear-induced graphitization mechanism.1 These films however, have inherent drawbacks such as high internal stresses, low fracture toughness and low thermal stability. Recent research efforts to alleviate the above problems have been focused into second phase additions in these films to synthesize nanoparticle or multi nanolayered composites. The presence of additional nano scale phases however, has important implications in the tribological mechanism and transfer layer formation and thus, has to be seriously considered. This paper discusses nano scale tribological mechanisms of such DLC-based films.