Instability of Diamond-like Carbon Films during Sliding in Aqueous Environments

Se Jun Park, Kwang-Ryeol Lee, Seung-Ho Ahn and Jung-Gu Kim
 

The instability of diamond-like carbon (DLC) film deposited on Ti-6Al-4V alloy substrate using the r.f.–PACVD method was investigated under sliding conditions in an aqueous environment. Significant adhesive wear was observed when tested in this environment, while normal abrasive wear occurred in an ambient air of relative humidity 25%. A critical test was performed to elucidate the reason for the instability which limits the biomedical applications of the DLC coating. By employing a multistep coating process, it was shown that the instability is closely related to the penetration of water molecules to the interface via through-film defects or pinholes.