Tribological performance of amorphous carbon films prepared on steel substrates with carbon implantation pre-treatment

The paper discusses the tribological performance of amorphous carbon films deposited on steel substrates with the pre-treatment of carbon ion implantation. Prior to deposition, the steel substrates were implanted with a metal vapour vacuum arc (MEVVA) ion source in order to create a carbon composition gradient layer on the surface. Subsequently, non-hydrogenated amorphous carbon films were prepared by a closed field unbalanced magnetron sputtering ion plating (CFUBMSIP) technique. The tribological tests using a conventional ball-on-disk tribometry showed that the films exhibited excellent performance during dry sliding. Low friction coefficients (<0.1) and almost zero wear rates were observed at a normal load of 70 N over 30,000 rotation cycles of unlubricated sliding against WC balls. In multi-pass reciprocating wear test under severe conditions (90 N load), the films on the implanted substrates could endure 16,000 passes; whereas the films with CCrx or Cr interlayers failed at the very beginning of the sliding.