Friction and wear properties of PTFE composites under different lubrication conditions

The friction and wear behavior of PTFE composites filled with carbon fiber (CF) and glass fiber (GF) under alkali, water, oil-lubricated and dry lubrication conditions were investigated. The wear mechanisms of the composites under different lubrication conditions were discussed based on the examinations of the worn ring and counterpart ring surfaces by means of SEM. It was found that the relationship of the friction coefficients and wear rate of the CF/PTFE and GF/PTFE composites sliding under different conditions was μ_dry > μ_{water or oil} > μ_alkali and W_water > W_dry > W_{alkali or oil}. The transfer onto the counterpart rings was significantly hindered by water, alkali and oil. Owing to the good stability, cooling and boundary lubrication capacity of alkali and oil-lubricated conditions, all PTFE composites filled with CF and GF showed much lower friction coefficients and wear rate. However, the bonding property of the interface was decreased by water. Abrasion and furrow were the main cause of the wear, leading to increasing wear rate of PTFE composites under water-lubricates condition.