Tribological behavior of carbon-filled PPS composites in water lubricated contacts

Abstract

The present study aims at investigating the tribological behavior of polyphenylene sulfide (PPS) composites in water lubricated sliding contact against a metallic (Inconel) counterpart. Factorial combinations of three commercially available carbon based fillers namely short carbon fibers (SCF), multi-walled carbon nanotubes (MWNT) and graphite (Gr) were utilized as single, dual- and multi-modal reinforcement.Reduction in wear of more than three orders of magnitude and a reduction in friction of more than 60% were achieved for the composite containing short carbon fibers as compared to neat PPS. However, incorporation of MWNTs and/or Gr marginally influenced the friction and wear behavior of the PPS composites. X-ray photoelectron spectroscopy (XPS) of the worn counter surfaces confirmed the formation of a reaction layer on the Inconel counterpart. Further investigations utilizing Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) revealed the formation of nano-tribo-layers on load bearing plateaus of the Inconel counter surface.It can be concluded that the sliding wear resistance of the short carbon fibers, the enhanced polymer transfer, and the formation of a nano-tribo-layer on the counter surface are mainly responsible for the outstanding tribological behavior of short carbon fiber reinforced PPS composites in water lubricated sliding conditions.