Influence of Temperature Correlations on Phase Kinetics of Boundary Friction

Using the Lorenz model for viscoelastic medium approximation 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 portraits are defined corresponding to the different regions of dynamic phase diagram and determining system’s kinetics. It is shown that the singular point, meeting the mode of dry friction, has indefinite character of stability. The other most probable steady-states of the system, corresponding to the stable and metastable sliding friction, are presented by the focus-type singular points in phase portraits. Consequently, the system can demonstrate damping oscillations near stable steady-states. The large extension of depicting trajectories near focuses along the axes of phase plane testifies to stability of sliding friction. Since maximums of distribution function, separated by the pronounced minimums of probability, correspond to the steady-state modes of friction, the transitions between them occur after large intervals of time.