Hydrothermal synthesized magnesium silicate hydroxide/graphene nanocomposites in a MgO-SiO2-graphite-H2O alkaline system and its application in anti-wear additive toward infinitesimal wear

摘要

The paper describes a hydrothermal synthesis of one new-style inorganic modified graphene nanomaterial called magnesium silicate hydroxide/graphene (MSH/graphene) in a MgO-SiO2-graphite-H2O system, and reveals its tribological behaviors as additives in poly-alpha-olefin (PAO). These MSH/graphene nanocomposites consist of MSH and various forms of graphene evolved from natural micmcrystalline graphite. Four-ball experiments indicate that MSH/graphene nanocomposites as additives in PAO display outstanding tribological performances and nearly eliminate wear despite a severe contact pressure of 3.91 GPa. This can be attributed to the attachment of graphene to MSH, enabling it to successfully enter the asperity clearances so as to bring into full play to graphene's extreme mechanical strength and/or forming a tribofilm consisting of nanocrystalline graphite and amorphous carbon (a-C) on the sliding surfaces.