Thermal Activation of Dry Sliding Friction at The Nano-scale

TL;DR

This study uses molecular dynamics simulations to explore how temperature affects nano-scale dry sliding friction, revealing that higher temperatures decrease the kinetic friction coefficient, consistent with thermal activation phenomena.

Contribution

It introduces a molecular dynamics approach to quantify the temperature dependence of kinetic friction at the nano-scale, linking thermal effects to atomic-scale friction behavior.

Findings

Kinetic friction coefficient decreases as temperature increases.

Friction force increases with sliding velocity.

Results align with thermal activation theory in atomic-scale friction.

Abstract

Molecular dynamic (MD) simulations are applied to investigate the dependency of the kinetic friction coefficient on the temperature at the nano-scale. The system is comprised of an aluminum spherical particle consisting of 32000 atoms in an FCC lattice sliding on a stack of several layers of graphene, and the simulations have done using LAMMPS. The interaction potential is charge-optimized many-body (COMB3) potential and a Langevin thermostat keep the system at a nearly constant temperature. With an assumption of linear viscous friction, $F_{fr}= - \gamma v$, the kinetic friction coefficient $\gamma$ is derived and plotted at different temperatures in the interval of $T \in [1, 600] K$. As a result, by increasing temperature, the kinetic friction coefficient is decreased. Consequently, while the friction is assumed as a linear viscous model, the results are similar to the thermal activation in atomic-scale friction. That is, (1) by increasing sliding velocity friction force will be increased and (2) by increasing temperature, kinetic friction coefficient decreases.