Wear behavior of silicon-containing diamond-like carbon coatings

The silicon-containing diamond-like carbon (DLC) films have been deposited on SKD61 steel by r.f. PECVD (plasma-enhanced chemical vapor deposition). A pin-on-disk wear test with a higher normal load, 30 and 40 N, was conducted to investigate the wear behavior of the DLC films. Various structures of the films obtained by different deposition conditions lead to different wear lives of the DLC-coated steels. A DLC film with small amount of silicon addition has a lower friction coefficient (0.01) than an undoped film (0.1). Raman analysis showed that in the wear test, graphitization of the pure DLC him occurs at the initial stage, whereas for the silicon-containing DLC film, graphitization of the wear debris or transferred film was not observed after the wear test, which indicates that the silicon-containing DLC film exhibits a better thermal stability than the pure DLC film. The lower friction coefficient value of silicon-doped DLC may be due to the formation of SiO2 that might arise from the contamination in the deposition system or oxidation in processing. (C) 1998 Elsevier Science S.A. All rights reserved.