Effects of Lubricants on the Friction and Wear Properties of PTFE and POM

The friction and wear properties of PTFE and POM were investigated using a ball-on-steel ring tester under dry and lubricated conditions by paraffin and 10W–30 oils. SEM, EDAX, FTIR, and surface wettability techniques were used to characterize and assess the morphology and chemical composition of the original surfaces, as well as the wear track, transfer film, and wear debris at different loads and speeds. Although the friction was high, similar behavior to that reported in the literature was observed. The experimentally determined surface temperature of the plastic revealed optimum loading levels, for each sliding speed, at which the friction and wear rate become a minimum and the thermal effect stabilizes. In boundary-like lubrication using both oils, friction and wear were significantly reduced with the exception of an increase in wear rate with load when POM was lubricated by 10W–30 oil. Surface analysis revealed that the formation of lubricative protective layers on the surfaces in contact is crucial to reducing friction, and more importantly, wear. FTIR results confirmed that film transfer occurs in the case of POM.