Influence of PTFE-based dry lubricants on friction and wear behavior in dry lubricated steel-bronze contact

In this paper, solid lubricants are investigated to examine their tribological performance in a dry lubricated steel-bronze contact. The examined solid lubricants are made of polyamide (PA) and irradiated polytetrafluoroethylene (PTFE), which are chemically bonded by reactive melt extrusion. For the tribological investigations, a block-twin-disc test rig on the one hand and a three-disc test rig on the other hand were used under ambient conditions, where the solid lubricant for lubricating the steel-bronze contact was released from a block or a disc. Results from the tribological investigations are presented here, showing the friction and wear behavior in a steel-bronze contact depending on the slide-to-roll ratio in the contact between the steel disc and the compound body. Furthermore, surface analytical investigations on the steel and bronze discs were carried out. These studies showed that the chemical bonding of 20 wt-% of irradiated PTFE in PA12 improves the wear and friction behavior in steel-bronze contact significantly, due to the build-up of a transfer film of PTFE on the steel surface.