Polytetrafluoroethylene (PTFE) is a self-lubricating matrix material with low friction coefficient and corrosion resistance but high wear rate. Ceramic particle fillers could effectively improve the tribological properties of PTFE-based composites, reduce its wear rate. However, there has been much debate about anti-wear mechanisms for particle fillers, which mainly focus on wear resistance micromechanism and mechanochemistry approach. In this paper, four kinds of PTFE-based composites filled with micrometer-sized ceramic particles (SiC, Si 3 N 4 , SiO 2 and h-BN) were prepared and tested to explore their tribology properties using a pin-on-disk tribometer. The filler proportions ranged from 5 to 20 wt% in 5 wt% increments were added. The worn surfaces of the composites and transfer films attached on the steel disk were examined by Scanning electron microscopy (SEM), energydispersive x-ray spectroscopy (EDS), Fourier-transform infrared (FTIR) and 3D topographies. Ultralow wear was observed on the PTFE/SiO 2 and PTFE/Si 3 N 4 composites in wear tests, which was attributed to tribochemistry. There were protection films formed on the worn surface, which hindered further transfer of the composites. Meanwhile, adhesion of the transfer film was enhanced by metalchelate salts of perfluorinated carboxylic acids formed by tribo-chemical reactions. The wear rate of PTFE decreased by three orders of magnitude (from 6.25 * 10 −4 to 2.21 * 10 −7 mm 3 /(Nm)) after addition of 20 wt% SiO 2 particles. No chemical reaction was observed on the worn surface of PTFE/ SiC and PTFE/h-BN composites.

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The tribology performance of two carbon fiber-reinforced polyether-ether-ketones (450FC30 and WG101) sliding against stainless steel 3Cr13 and 3Cr13 coated with aluminium oxide (Al2O3), tungsten carbide (WC) and diamond-like carbon (DLC) under dry friction and water lubrication were studied to reduce the coefficient of friction and improve the wear resistance of water-lubricated bearings. The friction and wear mechanism of different tribopairs were determined via pin-on-disc sliding tests. Experimental results showed that the WG101/Al2O3 tribopair exhibited excellent wear resistance under dry friction and water lubrication. Carbon fibers were exposed on the friction surface of WG101 when WG101 slid against Al2O3. These carbon fibers bore most of the load to reduce wear. This work provides a practical basis for selecting the optimal tribopair for water-lubricated bearings.