Friction and wear Properties in Fretting at Room Temperature and with Liquid Nitrogen

Abstract

The fretting wear properties of copper, SUS316L steel, epoxy and polyimide were examined at room temperature (293 K) and with liquid nitrogen (77 K) . Fretting conditions were a frequency of 8.3 Hz, a peak-to-peak slip amplitude of 100 μm, normal loads of 4, 10 and 20 N, and 5×10⁴ fretting cycles. The frictional properties against the fretting cycles were qualitatively independent of temperature for like-metal combinations. Temperature dependence was observed for metal and polymer combinations, that is, coefficients of friction increased after certain cycles at 293 K and were maintained constant at 77 K. Mean coefficients of friction at 77 K were higher than those at 293 K for like-metal combinations, while they were lower than those at 293 K for polymers against metals. Wear volumes at 77 K were less than those at 293 K for all combinations. These properties were affected by the change in mechanical properties of materials, the change in the oxidational process and the cooling effect by liquid nitrogen.