Improving the Tribological Properties of Spark-Anodized Titanium by Magnetron Sputtered Diamond-Like Carbon

Abstract

Spark-anodization of titanium can produce adherent and wear-resistant TiO 2 film on the surface, but the spark-anodized titanium has lots of surface micro-pores, resulting in an unstable and high friction coefficient against many counterparts. In this study, the diamond-like carbon (DLC) was introduced into the micro-pores of spark-anodized titanium by the magnetron sputtering technique and a TiO 2 /DLC composite coating was fabricated. The microstructure and tribological properties of TiO 2 /DLC composite coating were investigated and compared with the anodic TiO 2 mono-film and DLC mono-film. Results show that the DLC deposition significantly decreased the surface roughness and porosity of spark-anodized titanium. The fabricated TiO 2 /DLC composite coating exhibited a more stable and much lower friction coefficient than anodic TiO 2 mono-film. Although the friction coefficient of the composite coating and the DLC mono-film was similar under both light load and heavy load conditions, the wear life of the composite coating was about 43% longer than that of DLC mono-film under heavy load condition. The wear rate of titanium with protective composite coating was much lower than that of titanium with DLC mono-film. The superior low friction coefficient and wear rate of the TiO 2 /DLC composite coating make it a good candidate as protective coating on titanium alloys.

Low voltage environmentally friendly plasma electrolytic oxidation process for titanium alloys

“…Chen et al, reported a two-step process of producing carbon incorporated PEO treated titanium oxide coatings with improved tribological behaviour. The authors used magnetron sputtering to deposit diamond-like carbon into the micropores of PEO-treated commercial grade-2 titanium metal 19 . Nitrogenation of TiO 2 -based ceramic coatings is another well-researched method for improving their functionality; however, there are no reports of incorporating nitride content into PEO-treated titanium alloys by modifying the electrolyte composition.…”

Perspectives of the Friction Mechanism of Hydrogenated Diamond-Like Carbon Film in Air by Varying Sliding Velocity

“…Previously, lots of experimental studies on the tribological properties of DLC films have been carried out by investigating the effects of intrinsic properties, i.e., hydrogen concentration, hardness, metal/nonmetal doping, and so on [8][9][10][11]. However, the tribological properties of DLC films depend on not only the intrinsic parameters, but also many extrinsic factors, such as sliding velocity, normal load, environment atmosphere, and properties of friction interfaces [12][13][14][15]. In particular, the effect of sliding velocity on the friction characteristics of DLC films has been extensively studied, giving rise to a large amount of diverging findings [15][16][17].…”

Self-Lubricating PEO–PTFE Composite Coating on Titanium

“…This phenomenon was in connection with the unique structure of PEO TiO 2 coating. The PEO coating typically has a rough and porous outer layer and a dense inner layer [13]. The porous outer layer featured with high surface roughness and varied internal microstructure, which contributed to the high and unstable friction coefficient at the initial stage of the test.…”

“…In the previous study, we have explored depositing diamond-like carbon (DLC) on the PEO coating by using the unbalanced magnetron sputtering technique. Although results show that the TiO 2 /DLC composite coating exhibits improved tribological properties with low friction coefficient and low wear rate, DLC coating deposition is an expensive and time-consuming process [13]. Furthermore, this technique is not favorable to producing coatings on complex-shaped specimens.…”