Carbon and boron based 2D nanomaterials: efficient lubricant additives

Researchers are mainly concerned with minimizing friction and preventing the wear of moving mechanical components, since these problems create significant energy and economic constraints for many small-scale and large-scale mechanical industries. Nanomaterials, especially 2D nanostructures such as graphene and its derivatives graphene oxide or reduced graphene oxide (GO/rGO), and hexagonal boron nitride (h-BN), as additives in conventional lubricants attract significant attention because of the remarkable enhancement of anti-friction and anti-wear characteristics. This chapter aims to provide a detailed overview of recent developments in 2D nanomaterials dispersed in nanolubricants. The preparation of 2D nanomaterials, surface functionalization of graphene and h-BN using various chemicals/methods (oxidation, amine functionalization, alkylation, ionic liquids, and surface modifiers) and other nanoparticles, and their influences on the friction and wear behavior in nanolubricants are discussed in this chapter. Additive concentrations and their dispersion stability in lubricants, functional groups, and sliding conditions are the key determinants of the tribological properties of nanolubricants. The tribofilm formation mechanism and the impact of tribofilms on the anti-friction and anti-wear behavior of nanolubricants are also discussed in this chapter.