Controlling Mechanism of Temperature Dependence of Kinetic Friction of Ice

Ice friction is one of the major technical issues in almost every application involving ice as one of the moving parts. Very few studies have placed emphasis on the effects of temperature on ice friction at low velocities, although this is important in the transportation of heavy loads in cold regions using sleds, particularly at the onset of sled movement. In this study, a linear tribometer was designed to move a surface of ice over the test surfaces under constant sliding velocity and load. We present new experimental results of the kinetic friction of ice on stainless steel and polytetrafluoroethylene (PTFE) substrates at low velocities and a wide range of temperatures to a minimum of −60 °C. The results show a strong reduction in friction with increase in temperature. Low friction at low velocities and high temperatures may be owing to the thicker quasi-liquid water from pre-melting at the points of sliding contact, while high friction at low velocities and low temperatures can be caused by the low mobility of the surface molecules. The huge difference between the thermal conductivities of stainless steel and PTFE as well as the relatively high glass transition temperature of PTFE most likely account for the divergence of their coefficient of kinetic friction (COF) curves.