Environmental dependence of ultra-low wear behavior of polytetrafluoroethylene (PTFE) and alumina composites suggests tribochemical mechanisms

► Wear of PTFE/Al2O3 composites can be 4 to 5 orders of magnitude lower than PTFE. ► The reduction in wear is achieved by the inclusion of a few percent Al2O3 fillers. ► The wear rate of these composites is dependent on the environment. ► Wear rates increase as humidity decreases. ► A tribochemical process is responsible for the reduction in wear of PTFE by including Al2O3 fillers.