Wear Study of a Magnetron-Sputtered TiC/a-C Nanocomposite Coating under Media-Lubricated Oscillating Sliding Conditions

Abstract

Friction and wear performance of non-reactively magnetron-sputtered hydrogen-free TiC/a-C coatings were characterized under lubricated oscillating sliding conditions against 100Cr6 steel. The friction mediators, isooctane, ethanol and distilled water, were chosen to address the actual trend of environmentally friendly green technologies in mobility and the potential use of carbon-based nanocomposite thin film materials for tribocomponents in contact with gasoline and alternative biofuels. Sliding pairs of the TiC/a-C coatings showed significantly reduced friction and wear compared to the reference materials under both unlubricated and lubricated conditions (when using the aforementioned media isooctane, ethanol and distilled water). Quasi-stationary friction coefficient of the TiC/a-C sliding pairs after running-in was almost independent of test conditions and could be traced back to self-lubrication as a result of the formation of a transfer layer on the steel counter body. Wear of the coatings based on micro-abrasion and tribochemical reaction was significantly influenced by the environmental conditions. Lowest wear was measured after tests in non-polar isooctane whereas highest wear was measured after tests in water.

What Determines the Low-Friction Mechanism of the Silicon-Doped Diamond-like Carbon Film in a Water Environment: An Atomic-Level Understanding

“…Recently, many studies have revealed that incorporating silicon elements into DLC films can enhance their frictional characteristics in a water environment. − Some argued that the lower friction coefficient of Si-DLC films, in comparison to DLC films, can mainly be attributed to the colloidal silica produced due to chemical reactions initiated by friction at the sliding interface. − For instance, Oguri et al pointed out that the Si-DLC film exhibits superior low-friction properties when compared to the DLC film. This phenomenon is ascribed to the formation of a silicon sol at the friction interface.…”

Preparation and Performance Study of Si-DLC Based on Ion Deposition of Different Multiple Gradient Transition Layers

“…With the popularization of DLC coatings, silicon (Si) diamond-like films (Si-DLC) have been found to have higher hardness, smaller friction coefficient, higher wear resistance and better thermal stability performance [5][6][7]. The microstructure of Si-DLC films prepared by different methods and processes have great differences, which can affect various properties of Si-DLC films, giving theoretical and technical possibilities for the property adjustment of Si-DLC films.…”