FRICTION AND WEAR OF POLYMERIC MATERIALS AT 293-K, 77-K AND 4.2-K

Experiments were performed to determine the friction and wear coefficients of various polymer pins slid against either AISI 304 stainless steel or oxygen-free high conductivity (OFHC) copper at temperatures of 293, 77 and 4.2 K. Three kinds of polymeric materials were tested: 1, unfilled; 2, solid-lubricant filled; and 3, fabric- and particle-reinforced plastics. The polymers' penetration hardnesses were measured at 293 and 77 K to facilitate the wear coefficient calculations. Although the polymers were much harder at the cryogenic temperatures, it was found that their non-dimensional wear coefficients remained relatively constant, generally in the range 5 x 10(-7) -5 x 10(-6). Cross-plots of the polymers' wear coefficients versus the corresponding friction coefficients show good correlation and indicate a third- to fourth-power functional relationship between friction and wear for both the unfilled and the reinforced plastics. The magnitude of the wear coefficients and the relationship between friction and wear suggest that adhesive wear is the dominant wear mechanism for these polymers.