Tribological and rheological evaluation of a graphene nanosheets-based lubricant for metal-on-metal and wet clutch interfaces

• Published in: Materials letters 2022-02, Vol.309, p.131441, Article 131441
• Main Authors: Cao-Romero-Gallegos, Julio A., Farfan-Cabrera, Leonardo I., Pérez-González, José, Marín-Santibáñez, Benjamín M.
• Format: Article
• Language: English
• Subjects: Anti-shudder; Automatic transmissions; Evaluation; Graphene; Interface stability; Lubricants; Lubricants & lubrication; Materials science; Mineral oils; Nanolubricant; Nanosheets; Pin-on-disc; Rheological properties; Rheology; Shear flow; Shear thinning (liquids); Thermal stability; Thermogravimetric analysis; Tribology; Viscosity; Wear rate; Wet clutch; Wet clutches
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2021.131441

•The tribological and rheological behavior of mineral oil with GNS was analyzed.•Mineral oil with GNS become non-Newtonian shear-thinning.•The addition of GNS to mineral oil reduced significantly wear rate for metallic interfaces.•Adding 1.0 w/v% of GNS to mineral oil enhanced the ∂µ/∂v behavior of a wet clutch.•Adding 1.0 w/v% of GNS to mineral oil enhanced its thermo-oxidation resistance. The tribological and rheological behavior of mineral oil (MO) additivated with graphene nano-sheets (GNS) as lubricant in metal-on-metal interfaces and actual wet clutch materials was analyzed in this work with a focus on its potential use in automatic transmission (AT) systems. Lubricants prepared with different GNS concentrations (0.1, 0.5, 1.0 w/v%) in MO were evaluated in shear flow (viscosity changes) and by ball-on-disc measurements. Besides, thermogravimetric analysis and wet clutch friction tests at 26 and 100 °C were performed. Overall, the GNS addition to MO made the lubricants non-Newtonian shear-thinning and increased their viscosity at high shear rates, reduced the wear rate for the metallic interfaces tested, and enhanced the thermal stability and oil anti-shudder property of the wet clutch.