Friction and Wear Behaviors of Kevlar/Polytetrafluoroethylene Braided Composite in Oscillatory Contacts

The self-lubricating braided composite used in oscillating bearing was tested and evaluated under the extreme operating conditions. The Kevlar/PTFE braided composite was investigated on an oscillatory high load (> 30 MPa) and high frequency (> 2 Hz) tester with oscillating frequency ranging from 2.5 to 10 Hz and load from 30 to 50 MPa. Effects of the oscillating frequency and load on the friction coefficient and wear loss were obtained. Results show that the friction coefficient is mainly affected by oscillating frequency under higher loads. It firstly decreases with frequency and later is toward dynamic stability and fluctuates regionally with varying load. Friction surface and wear debris were analyzed under varied load and oscillating frequency using scanning electron microscope. Effects of the oscillating frequency and load on the friction coefficient and wear loss of the Kevlar/PTFE braided composite under high load condition were discussed. It is obtained that the friction surface is mainly damaged due to high frequency rather than high load. This study could provide a basis for performance matching and selection of composite under varied operating conditions.