Simultaneous Control of Sliding Contact and Oxidation via Graphene-Based Materials

Abstract

Friction and wear, which originate as a consequence of contact sliding, remain critical concerns. In many systems, friction causes 20−30% wastage of energy, while wear leads to premature failure of systems. Oxidation/corrosion is another major concern that limits the functionality and durability of components. Here, employing experiments and atomistic simulations, we demonstrate that single-layer graphene (SLG) adequately reduces the friction and wear of a metal and provides excellent oxidation protection. But beyond certain initial contact cycles, its coefficient of friction (COF) continuously increases from ∼0.15 with progressing sliding cycles. In contrast, multilayer graphene (MGR) always maintains low friction (COF ≤ 0.1) and achieves relatively better wear resistance. Nevertheless, atomic thickness and realized good tribological and oxidation protection properties still make SLG a crucial candidate for many systems with constraint overcoat thickness such as magnetic storage devices and micro-/ nano-electromechanical systems. The tribological properties of SLG and MGR are also compared with solution-based graphite coatings and plasma-grown diamond-like carbon coating. Through spectroscopic and microscopic characterizations, along with atomistic simulations and hypothetical models, we discover and present the friction and wear mechanisms of these tribo-systems. This work uncovers the critical sliding behavior of carbon-based systems for advancing and enabling sustainable moving mechanical technologies.