3D morphologies of wear tracks: a wear track in ambient air and b wear track in water

Diamond-like carbon (DLC) films have caught much attention owing to their excellent mechanical and tribological performance. However, the true DLC films are very hard with high internal stresses and have poor adhesion, which make them unsuitable for highly loaded applications. In order to reduce the internal stresses, the DLC films were doped with various metals. The weakness of the high wear rates at a high relative humidity has not been solved. This leads to the limitation to the wide use of DLC films in humidity environment, especially in water hydraulic systems.

Researchers of the State Key Laboratory of Solid Lubrication of the Lanzhou Institute of Chemical Physics (LICP), CAS, have fabricated nanocomposite graphite-like carbon (GLC) films with high hard of about 23 GPa by DC magnetron sputtering using a graphite target. However, it was found that various nanocrystallites embed the amorphous matrix inside the as-deposited GLC films which are different from the other GLC films with very high hardness reported before. After testing in ambient air and distilled water, the as-deposited nanocomposite GLC films presented self-adapted excellent tribological properties in these two environments. A different strengthening mechanism in the GLC films was proposed, and the factors to their excellent tribological properties both in ambient air and water environment were evaluated.

The as-deposited hard nanocomposite GLC films have excellent self-adopt tribological properties in different environments of ambient air, different relative humidity and water, and it is thought to have great potential in protecting and solid lubricating material in ambient humidity and water environment.

The work has received support from the National Natural Science Foundation of China and High Technology Research and Development Program of China. The findings have been published in Tribol Lett (Tribol Lett (2010) 40:301–310).

Tribol Lett  Paper