Friction and wear characterization of graphite/Polytetrafluoroethylene composites against stainless steel: A comparative investigation under different environments

Abstract The friction and wear characteristics of Polytetrafluoroethylene composites filled with 15 wt.% and 25 wt.% graphite were investigated against stainless steel under dry sliding and in aqueous environments. A pin on disc tribometer was employed for experimentation at room temperature. The friction performance of 15 wt.% Graphite/Polytetrafluoroethylene proved better than 25 wt.% Graphite/Polytetrafluoroethylene under all conditions, however the wear performance was better for 25 wt. % Graphite/Polytetrafluoroethylene. Moreover, the tribological behaviour of all the composites enhanced in natural sea water environment. An average COF (0.02) and wear rate (1.27 × 10 -5 mm 3 /Nm) were attained for 15 wt. % Graphite/Polytetrafluoroethylene in sea water; and an average COF (0.0293) and wear rate (5.2 × 10 -6 mm 3 /Nm) were obtained for 25 wt. % Graphite/Polytetrafluoroethylene in sea water. From SEM analysis it was revealed that the better tribological performance of graphite/Polytetrafluoroethylene in sea water is due to the formation of lubricious films on the surfaces in sea water.