Tribological Properties of PTFE Composites under Water and Oil Lubrication Conditions

Two kinds of polytetrafluoroethylene (PTFE) based composites were prepared by adding carbon fibers (CF) and bronze powders (Cu) respectively, and then they were matched with 42CrMo steel rings to form friction pairs. The tribological properties of these two PTFE composites were studied under dry friction, water lubrication and oil lubrication conditions. The worn surface morphology of the composites was observed by SEM, and the wear mechanism was analyzed. The results show that under dry friction and oil lubrication conditions, the friction coefficient of CF/PTFE composites increased with the increase of carbon fiber content, while the scar width decreased. The friction coefficient of the two composites was maximum under dry friction condition and was minimum under oil lubrication condition. And under the oil lubrication condition, the scar width of the two PTFE composites was minimum. The friction coefficient under the water lubrication condition was smaller than that under dry friction condition, but the scar width was bigger. The wear mechanism of CF/PTFE composites was mainly fatigue wear, and the furrow morphology was not obvious. The wear mechanism of Cu/PTFE composites was mainly abrasive wear accompanied by fatigue wear, and the furrow morphology was obvious.