Friction and wear at low temperatures

For investigations of the friction and wear behaviour of materials under cryogenic conditions a special test device (Cryotribometer) has been constructed. The friction tests are performed with samples in a pin-on-disc configuration in a He-gas environment at temperatures between 8 and 77 K. Most of the tests were performed with filled and unfilled polymers like polyterafluorethylene (PTFE), polyamide (PA), polyoxymethylene (POM) and polyimide (PI) against steel. Compared to room temperature most polymers have an improved frictional behaviour in dry sliding at low temperatures, due to their increasing hardness and mechanical strength. Some experiments with hard carbon coatings indicate that the running-in and wear behaviour of these materials is influenced mainly by temperature. (C) 1998 International Association for Hydrogen Energy.