Effect of Polytetrafluoroethylene on Wear Properties and Extreme Load Carrying Properties of Lubricating Oil

Abstract

In this paper, optimization of ultrasonication process to improve the mixing of polytetrafluoroethylene (PTFE) in lubricating oil has been done. The effect of PTFE on wear preventing and extreme pressure (EP) properties of lubricating oil with AISI 52100 steel balls were studied using four ball testers. The composition of oil lubricants changed by adding 0.5 wt% to 4.0 wt % of PTFE powder. Initially ultrasonic treatment was given to PTFE powder for proper mixing of PTFE powder in lubricating oil. Values of wear scar diameter with respect to applied load, extreme pressure values i.e. weld point value were tested for various PTFE compositions in oil. Wear scar diameter (WSD) was measured with optical microscope results show a reduction of average scar in the three lower balls and the increase in the welding point. The oil sample with higher PTFE percentage had higher welding loads and the smaller scar diameter for the same load. Coefficient of friction for both with and without PTFE additive mixed lubricating oil is estimated experimentally.  The topography of ball specimens was examined using 60 mm macro lens canon 1000D camera. The observed wear response of the sample has been substantiated through the characteristics of wear surface.