Tribological Performance of PPS Composites under Diesel-lubricated Conditions

Several kinds of polyphenylene sulfide composites (PPS-coms), filled with 10% short carbon fibers (SCF), copper (Cu), copper oxide (CuO) and copper sulfide (CuS) micro-particles were prepared by hot press molding, respectively. The tribological behaviors of the PPS materials were investigated by a friction and wear tester under diesel lubrication, the worn surface morphology, transfer film structures and tribochemistry were analyzed, based on which the tribological mechanisms were explored. It is demonstrated that the tribological properties of PPS composites were improved to some extent when the micro-particles were filled. The addition of SCF into PPS matrix greatly enhanced the wear resistance, while the addition of Cu and CuS particles led to obvious reduction of the friction coefficient. On this basis, the effects of two combined fillers SCF/Cu and SCF/CuS on the tribological properties of PPS composites were further investigated. It was identified that the combined fillers SCF and CuS played a synergetic role in improving the tribological performance. Low friction coefficient and high wear resistance were achieved by filling PPS with the combined fillers. It was revealed that SCF enhanced the load-bearing capacity and abrasion resistance of PPS material, whilst CuS promoted beneficial tribo-chemical reactions leading to the formation of a high performance tribofilm.