Achieving ultra‐low friction of a‐C:H film grown on 9Cr18Mo steel for industrial application via programmable high power pulse magnetron sputtering.

Owing to the high hardness and hydrogen passivation of carbon bonds, hydrogenated diamond‐like carbon (a‐C:H) film has shown promising potential to achieve ultra‐low friction and wear on steel surfaces. Here, a‐C:H film was successfully deposited on 9Cr18Mo steel via programmable high power pulse magnetron sputtering and potential application for industrial was evaluated. The a‐C:H films against different mating materials of GCr15 steel balls, Al2O3, Si3N4, ZrO2, and a‐C:H‐coated GCr15 balls all showed ultra‐low friction under a normal load of 5 N in a dry ambient air environment. Among them, self‐mating tribo‐system a‐C:H films on steel surfaces and a‐C:H‐coated steel balls achieve best friction performance; the principal reason is that both contacting surfaces coated with a‐C:H film have the lower electron affinities compared with other tribo‐systems. However, the differences of coefficient of friction (COF) for uncoated‐GCr15, Al2O3, ZrO2, Si3N4, and a‐C:H(GCr15) balls can be attributed to different sizes of clustering in wear debris. This work provides new insights on synthesis and industry application of the a‐C:H films with ultra‐low friction properties. [ABSTRACT FROM AUTHOR]