Preparation of superior lubricious amorphous carbon films co-doped by silicon and aluminum

Silicon (Si) and aluminum (Al) co-doped amorphous carbon films ((Si, Al)-C:H) were deposited on Si and stainless steel substrates by radio frequency (13.56 MHz) magnetron sputtering. The Al and Si were found to jointly regulate the hybridized carbon bonds. Mechanical properties of the films were detected by nano-indention and scratch tests. The nano-indention results revealed that all the samples exhibited good elastic recovery rate, among which the highest one was beyond 84%. Besides co-regulating the hybridizations of carbon, the co-doped Si and Al also had a common regulation on the mechanical and tribological properties. Especially, the film containing 1.6 at. % of Si and 0.9 at. % of Al showed a super-low friction (< 0.01) and a superior wear resistance in ambient air.