Enhanced lubricating properties of oils containing graphene synthesized in atmospheric plasmas

Abstract

The use of gas-phase-synthesized graphene (GSG) as a lubricant additive that is capable of significantly enhancing the tribological properties of widely used oils is reported herein. GSG is pure, highly ordered, and exhibits an inherently crumpled morphology that causes the nanomaterial to self-disperse and resist aggregation in base oils and fully formulated lubricants. Micro-tribometer tests revealed that the wear of sliding surfaces was significantly reduced by up to 53% when relatively minute amounts of GSG (≤ 0.1 wt%) was added to canola oil, polyalphaolefin (PAO), fully-formulated petroleum oil, and fully-formulated full synthetic oil. Additionally, the wear reduction of surfaces caused by GSG remained consistent as the concentration of the nanomaterial was reduced in PAO, which indicates that GSG concentrations below 0.025 wt% in base oil could achieve similar reductions in wear. A controllable GSG segregation phenomenon in PAO is reported, which has the potential to enable the controlled wear of sliding surfaces and the recycling of GSG additives. GSG is produced in a single step through an environmentally friendly atmospheric plasma process. Our results demonstrate that GSG holds promise as a sustainable and effective anti-wear additive for lubricants used in engines and other tribological applications.

Keywords

• Graphene
• Tribology
• Lubrication
• Crumpled graphene
• Gas phase synthesis