Friction and wear resistance of polytetrafluoroethylene-based composites reinforced with ceramic particles under aqueous environment

Abstract

Polytetrafluoroethylene (PTFE) exhibits excellent potential under aqueous lubrication due to its low water absorption, low friction, and good corrosion resistance. However, its poor wear resistance limits its application. In this paper, PTFE was reinforced with different kinds of ceramic particles, and the physical properties were tested using various methods. The tribological behavior of PTFE composites sliding against a super duplex stainless steel was investigated under deionized water and seawater lubrication. The worn surface was examined by scanning electron microscopy, energy-dispersive spectroscopy, and 3D topography. All four kinds of ceramic fillers promoted the crystallinity of the PTFE matrix. Particle-reinforced PTFE showed better tribological performance under seawater than under deionized water. The fragility of ceramic particles played an important role in the anti-wear performance of the PTFE composites. Breaking and shedding of Si3N4 or SiO2 particles would generate and aggravate abrasive wear between friction pairs. With the good crush resistance of SiC particles and seawater lubrication effect, the wear rate of the composite decreased by 80% in seawater compared with pure PTFE. The h-BN-filled PTFE showed a good and stable tribological performance under water and seawater because of the low interlaminar shear strength of h-BN.