Multi-layer interface lubrication of in-situ synthesized titanium dioxide/reduced graphene oxide nanocomposites

The poor dispersion stability and inferior anti-damage performance of single component graphene limit its industrial application as lubricating oil additives. Herein, titanium dioxide/reduced graphene oxide (TiO2/rGO) nanocomposites were prepared by a hydrothermal method as an oil-based lubricant additive. Raman and Fourier transform infrared spectra verified the generation of interfacial interaction between TiO2 (size of 4–9 nm) and rGO. Among them, the 0.08 wt% TiO2/rGO nanocomposites exhibited prominent thermal stability, high dispersion and excellent tribological performance, achieving 28.4% and 70.7% reduction in average friction coefficient and wear volumes compared with based oils, respectively. The formation process of dense and stable multi-layer tribo-film induces the reorganization of the sliding interface, for reducing friction and wear between friction pairs. More interestingly, through the analysis of worn surfaces and debris, the enhancement on TiO2/rGO stability caused by their interfacial interaction prevents the structure of rGO from being destroyed, forming the tough tribo-film. Meanwhile, TiO2 acting as the nano-bearing mechanism played the crucial role in friction reduction. Environmentally friendly preparation and efficient lubrication make TiO2/rGO a potential compound lubricating additive.