Tribological behavior of hydrogenated and non-hydrogenated diamond-like carbon coatings in dry and lubricated sliding.

摘要

Friction and material transfer mechanisms during sliding between 319 Al pin and hydrogenated diamond-like carbon (H-DLC) and non-hydrogenated diamond-like carbon (NH-DLC) coatings were investigated under ambient, humid air and vacuum. The coefficients of friction (COF) of H-DLC and NH-DLC were governed by the formation of carbon rich layers on the counterface.;H-DLC produced a lower COF of 0.05 in dry sliding compared to 0.1 in boundary lubricated sliding, indicating that this coating is more effective without the addition of lubricants. During lubricated sliding testes against AISI 52100 steel NH-DLC produced a lower COF compared to H-DLC and induced an earlier transition from the boundary to the mixed lubrication regime. This early transition was a result of the NH-DLC wearing down the steel counterface and increasing the contact area, prompting a reduction in contact pressure.