Effect of a hydrogenated interface on the wear behavior of a diamond-like carbon film in a water environment

Abstract

Hydrogenated diamond-like carbon (DLC) films or DLC films with hydrogenated interlayers tend to undergo early stage failure in water environments for reasons that are not fully understood. In this paper, a hydrogenated interface was prepared between a hydrogen free DLC film and a CoCrMo substrate, and the effects of the hydrogenated interface on the film structure, hardness, adhesion, wear behavior and corrosion resistance were investigated. The hydrogen free DLC films on the hydrogenated and the hydrogen free substrates exhibited similar structures and mechanical properties. The DLC films on both the hydrogenated and the virgin CoCrMo substrates exhibited good adhesion. The adhesions of the DLC films on both the substrates were not deteriorated after 150days of immersion in 0.9% NaCl solution. The wear resistance of the DLC film on the hydrogenated CoCrMo substrate was worse than that on the virgin CoCrMo substrate in water. The presence of hydrogen improved the activity of the interface, restrained the formation of a passivation layer, and promoted the corrosion of the interface, which caused early stage failure of the DLC film in water. Therefore, the hydrogenated interface has a negative effect on the wear behaviors of DLC films in water environments.