Impacts of potential energy oscillations on the friction of graphene and BN lubricants

Abstract

The frictional responses of graphene and boron nitride lubricants is studied from the perspective of the potential energy evolution. At a low normal load regime and high interface adhesion, friction can be effectively characterized by investigating the interfacial energy barrier formation process. By decomposing the energy evolution into strain and interfacial cohesive components, we find that the oscillation phase difference plays an essential role in the friction response and is controlled by the energy conversion between them. Analyses further reveal that the energy oscillations are excited by the vertical motion of the sliding asperity that induces periodic deformation and position changes in the lubrication systems. These new findings suggest the study of potential energy evolution is advantageous for understanding adhesive friction and infers the potential to leverage adhesion in 2D lubricant application through high conversion efficiency and out-of-phase oscillations between strain and cohesive energies.

Keywords

• strain-cohesive energy conversion
• energy oscillation phase difference
• adhesive contact
• single asperity friction