Effects of fibrous fillers on friction and wear properties of polytetrafluoroethylene composites under dry or wet conditions

The friction and wear behavior and mechanism as well as the mechanical properties of polytetrafluoroethylene (PTFE) composites filled with potassium titanate whiskers (PTW) and short carbon fibers (CF) under dry, wet and alkaline conditions were investigated. Experiments indicated that owing to appropriate cooling and boundary lubricating effects, the filled PTFE composites showed much lower frictional coefficient and better wear resistance under alkaline than dry and wet sliding conditions. The wear resistance of carbon-fiber-filled PTFE was much better than that of potassium titanate-whisker-filled PTFE composites in water. Results also showed that the transfer film on counterpart rings was significantly hindered by water and alkali. Hydrophilic-filler-reinforced PTFE composites yield higher wear rate when sliding under water.