Advisor(s)
Abstract(s)
Diamond-like carbon (DLC) coatings are widely used in industries that require high durability
and wear resistance, and low friction. The unique characteristics of DLC coatings allow for
the possibility of creating adsorption sites for lubricant additives through the doping process. In
this study, the combined use of europium-doped diamond-like carbon (Eu-DLC), gadolinium-doped
diamond-like carbon (Gd-DLC), and pure DLC coatings and an ionic liquid (IL) additive, namely,
trihexyltetradecylphosphonium bis (2-ethylhexyl) phosphate [P66614] [DEHP], with a 1 wt.% concentration
in polyalphaolefin (PAO) 8 as a base lubricant was investigated. Higher hardness, higher
thin-film adhesion, a higher ratio of hardness to elastic modulus, and a higher plastic deformation
resistance factor were achieved with the Gd-DLC coating. The CoF of the Gd-DLC coating paired
with the IL was superior compared to the other pairs in all lubrication regimes, and the pure DLC
coating had a better performance than the Eu-DLC coating. The wear could not be quantified due to
the low wear on the surface of the DLC coatings. The friction reduction demonstrates that tribological
systems combining Gd-DLC thin films with an IL can be a potential candidate for future research
and development efforts to reduce friction and increase the efficiency of moving parts in internal
combustion engines, for instance.
Description
Keywords
ionic liquid doped DLC lubrication regime Stribeck curve friction
Citation
Sadeghi, M.; Omiya, T.; Fernandes, F.; Vilhena, L.; Ramalho, A.; Ferreira, F. Tribological Behavior of Doped DLC Coatings in the Presence of Ionic Liquid Additive under Different Lubrication Regimes. Coatings 2023, 13, 891.