The Effect of Ambient Temperature and Grease Lubrication on the Tribological Properties of POM/PTFE Composites

Abstract

Abstract. Polyoxymethylene (POM) is widely used as a gear material due to its excellent properties. To explore the feasibility of using POM composites as gear materials in high-temperature environments, this study investigates the effect of ambient temperature (25–90 °C) on the tribological performance of POM/15wt% Polytetrafluoroethylene (PTFE) composites under self-mated contact, with and without grease lubrication. The results indicate that under dry friction conditions, the friction coefficient of the composite decreases with increasing ambient temperature at a low sliding speed of 0.1 m/s, whereas it increases with temperature at a higher sliding speed of 0.5 m/s. Under grease lubrication, the friction coefficient consistently decreases with increasing ambient temperature. Regardless of lubrication conditions, the specific wear-rate of the composite increases with rising ambient temperature. The addition of grease reduces the friction coefficient by 58.8%–81.1% and decreases the specific wear-rate by at least one order of magnitude. Under dry friction, the primary wear mechanism at low sliding speed is abrasive wear, transitioning to adhesive wear at higher sliding speed. In contrast, under grease lubrication, the dominant wear mechanism is fatigue wear.