Effects of PTFE coating modification on tribological properties of PTFE/aramid self-lubricating fabric composite

Polytetrafluoroethylene (PTFE)/aramid fabric composites are currently widely used as self-lubricating bearing liners. In this study, a PTFE composite coating was performed to improve the friction stability of the PTFE/aramid fabric composite in long-term friction. Effects of the surface modification on the composite tribological properties were studied using ball-on-disk friction tests. Results showed that under different sliding condition, the friction coefficient of the modified and unmodified fabric composite were similar after sliding of 240 min. However, the friction coefficient curves of the unmodified fabric composite increased first, then decreased, and then increased, while that of the modified fabric composite increased first and then stabilized. At a sliding speed of 4.5 m min(-1) and load of 50 N, the unmodified fabric composite worn out at similar to 200 min, but the modified fabric composite was still stable after 240 min. SEM results confirmed that the PTFE composite coating had a good film forming property, which improved the wear resistance and friction stability of the composite in long-term friction especially under high sliding speed. These results give a reference for the development of self-lubricating plain bearing liners with long lifespans.