Assessment of Nano-Scratch Resistance of Diamond-Like Carbon Films

Diamond-like carbon (DLC) films were prepared on Ti alloy substrate with an rf- plasma enhanced chemical vapor deposition method (rf PECVD), their nano-mechanical properties were evaluated by using a Nano Indenter system with attachments of Continues Stiffoess Measure- ment (CSM) and lateral force measurement (LFM). The results show that the hardness of those films increases with film thickness, but their increment is small; during scratching, three processes containing fully elastic recovery, asynchronous recovery of films and substrate, and delaminating of films, successively occur as the increase of load; at the first regime, no damage could be found on the surface of films, in the second regime, the trace like fish bone formed; as the thickness of films increases, the critical load increases, but the delamination of films is more severe, which may be attributed to the increase of internal stress in the films.