Preparation and tribological properties of novel boehmite/graphene oxide nano-hybrid

Novel boehmite/graphene oxide nano-hybrid (GO-GPTS-AlOOH) was prepared through a simple covalent bond method, which was subsequently explored as lubricant additive. For this purpose, the 3-glycidoxypropyl-trimethoxysilane (GPTS) was first chemically grafted on nano-boehmite (AlOOH) to fabricate the modified boehmite (GPTS-AlOOH). Then the GPTS-AlOOH was anchored on graphene oxide (GO) nanosheets to prepare GO-GPTS-AlOOH nano-hybrid through a coupled reaction. The structure, composition and morphology of GO-GPTS-AlOOH was characterized by FT-IR, XRD, TG/DTG, SEM and TEM, revealing that nano-boehmite was uniformly coated on GO surface. More importantly, tribological properties of GO-GPTS-AlOOH as lubricating oil additive were investigated using a ball-on-disc testing machine and a four-ball machine. It was found that the friction reduction and anti-wear ability of lubricant oil containing GO-GPTS-AlOOH hybrid was highly improved compared to bare base oil (VHVI8). Specifically, friction coefficient (COF), wear scar diameter (WSD) and wear rate were reduced by 14%, 28% and 73%, respectively. The enhancement can be attributed to the synergistic effect of the nanobearing mechanism and ultimate strengthen of graphene sheets between the frictional interfaces.