Enhanced Tribological Performance of Aminated Nano-Silica Modified Graphene Oxide as Water-Based Lubricant Additive

Improving the tribological properties of water by adding nanomaterials as water-based lubricant additive has garnered increasing interest for the great potential in range of water-based applications. However, combining ideally two-dimensional layered nanomaterials and zero-dimensional nanoparticles to create synergistic enhancement of lubricating performance under water is still challenging. In this paper, a novel nanomaterial named aminated silica modified graphene oxide (SAG), which combines the layered nanomaterial graphene oxide (GO) and the nanoparticles hydrophilic nanosilica (SiO2) by 3-aminopropyltriethoxysilane (APTES), has been synthesized. The tribological properties of the SAG nanomaterial as additives in deionized water (DI water) are evaluated on a CSM tribometer under high contact pressure. Using the SAG nanomaterial in DI water, besides the very low friction coefficient it produces, dramatically reduces the wear rate of the wear track and especially the ball. More importantly, the SAG nanomaterial outperforms the individual GO and nanosilica in improving wear resistance. The SAG can also prevent the diamond like carbon (DLC) films deposited on the steel substrates from tearing. It is suggested that the excellent mechanical property of GO nanosheets and the microscopic ball-bearings effect of silica nanoparticles, on which is the SAG nanomaterial based, account for the lubricating and antiwear action. As water-based lubricant additives, this novel nanomaterial showing excellent tribological properties is believed to be a potential candidate for water-based lubrication.