Tribological Performance Improvement of Polyamide against Steel Using Polymer Coating

Polyamide (PA) is used in industrial applications such as automotive, gears, bearings, and pipeline spacers. As a bearing material, PA can support high contact pressures under low sliding speeds. To achieve high-performing and durable contacts, it is necessary to have low friction, low vibration, and low wear between PA and steel contacts at different operating temperatures. This study proposes the use of an advanced polymer coating, namely, aromatic thermosetting copolyester (ATSP), on the steel surface and investigates the friction and wear properties between PA–ATSP coating and PA–steel at environmental temperatures of 25, 50, and 80 °C. The experiments were carried out using a pin-on-disc configuration under unlubricated sliding conditions. The results showed excellent performance of the coating on reducing the coefficient of friction (COF) by 80% and PA wear by 95% compared to bare steel. The ATSP coating worked as a predeposited transfer layer and showed nonmeasurable wear under moderate to high contact pressure conditions at all temperatures. The worn surfaces and the formation of transfer layers were further examined using scanning electron microscopy and energy-dispersive X-ray spectroscopy.