Tribological performance study of low-friction PEEK composites under different lubrication conditions

Abstract

Abstract To improve the friction and wear performance of polyetheretherketone (PEEK). In this paper, a low-friction PEEK-based composite with PEEK as the matrix material, polytetrafluoroethylene (PTFE) as the solid lubricant, and poly-p-phenylene-terephthamide (PPTA) as the reinforcing material were prepared by compression molding technique, and then the optimal preparation condition for PEEK was gained by exploratory experiments. Finally, the tribological performance of PTFE/PPTA/PEEK composites was researched under dry friction and oil lubrication conditions. The microstructure of the wear mark was observed by scanning electron microscope and white light interference microscope, and the wear mechanism of PEEK and its composites under different lubrication conditions were analyzed. The results show that the main wear mechanisms of the friction pair consisting of PTFE/PPTA/PEEK composites and bearing steel are ploughing and adhesive wear. When the friction pair slides, PPTA reduces the wear of the composite caused by its high fiber strength and good thermal stability, and the coefficient of friction (COF) is reduced because the PTFE on the surface is pressed into a smooth, solid lubricating film. Whether under dry friction or oil lubrication conditions, the PEEK composites containing 25wt% PTFE and 6wt% PPTA both have the lowest wear and lower COF.