Tribological behavior of micrometer- and nanometer-Al₂O₃-particle-filled poly(phthalazine ether sulfone ketone) copolymer composites used as frictional materials

Micrometer- and nanometer-Al₂O₃-particle-filled poly(phthalazine ether sulfone ketone) (PPESK) composites with filler volume fractions ranging from 1 to 12.5 vol % were prepared by hot compression molding. We evaluated the tribological behaviors of the PPESK composites with the block-on-ring test rig by sliding PPESK-based composite blocks against a mild carbon steel ring under dry-friction conditions. The effects of different temperatures on the wear rate of the PPESK composites were also investigated with a ball-on-disc test rig. The wear debris and the worn surfaces of the PPESK composites were investigated with scanning electron microscopy, and the structures of the PPESK composites were analyzed with IR spectra. The lowest wear rate, 7.31 × 10⁻⁶ mm³ N⁻¹ m⁻¹, was obtained for the composite filled with 1 vol %-nanometer Al₂O₃ particles. The composite with nanometer particles exhibited a higher friction coefficient (0.58–0.64) than unfilled PPESK (0.55). The wear rate of 1 vol %-nanometer-Al₂O₃-particle-filled PPESK was stable and was lower than that of unfilled PPESK from the ambient temperature to 270°C. We anticipate that 1 vol %-nanometer-Al₂O₃-particle-filled PPESK can be used as a good frictional material. We also found that micrometer-Al₂O₃-particle-filled PPESK had a lower friction coefficient at a filler volume fraction below 5%. The filling of micrometer Al₂O₃ particles greatly increased the wear resistance of PPESK under filler volume fractions from 1 to 12.5%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 993–1001, 2005