Influence of temperature correlations on phase dynamics and kinetics of ultrathin lubricant film

TL;DR

This study investigates how temperature fluctuations influence phase transitions and friction behavior in ultrathin lubricant films, revealing complex stick-slip domains and the impact of temperature correlation times on sliding friction.

Contribution

It introduces a model incorporating temperature correlations via Ornstein-Uhlenbeck process to analyze phase diagrams and friction regimes in ultrathin lubricants.

Findings

Presence of stick-slip friction domains in different phase transition cases

Increase in temperature correlation time raises the temperature needed for sliding friction

Complex stability behavior at the dry friction mode

Abstract

The melting of ultrathin lubricant film is studied by friction between atomically flat surfaces. The fluctuations of lubricant temperature are taken into account defined by Ornstein-Uhlenbeck process. The phase diagrams and portraits are calculated for the cases of second-order and first-order transitions -- the melting of amorphous and crystalline lubricants. It is shown that in the first case the stick-slip friction domain appears, dividing the regions of dry and sliding friction. In the second case the three stick-slip friction domains arise characterized by transitions between dry, metastable and stable sliding friction. The increase of correlation time of the lubricant temperature fluctuations leads to increasing of the frictional surfaces temperature needed for realization of sliding friction. The singular point, meeting the mode of dry friction, has complex character of stability. The stationary states, corresponding to the stable and metastable sliding friction, are presented by the focus-type singular points.