Temperature dependence of friction under cryogenic conditions in vacuum

We have constructed a sliding block cryotribometer designed to measure friction at cryogenic temperatures and UHV conditions. An optical cryostat and high speed video was used to monitor the motion of the block. The temperature range of the measurements was 4-460 K. Both the static and dynamic friction coefficients were determined for a steel ball on stainless steel, sapphire, and PTFE (Teflon) plates, and for a sapphire ball on a sapphire plate. For all material combinations, no systematic variation of friction with temperature was observed in the temperature range 4-200 K.