Synergetic Effect of Lubricant Additive and Reinforcement Additive on the Tribological Behaviors of PEEK-Based Composites under Seawater Lubrication

Polyetheretherketone (PEEK)-based composites reinforced with lubricant additive (polytetrafluoroethylene, PTFE) and reinforcement additives including carbon fiber (CF), glass fiber (GF), and bronze powder were prepared using a hot-press molding technique. The synergetic effects of different additives on the tribological behaviors of PEEK-based composites sliding against 316 steel under seawater lubrication were investigated systematically using a ring-on-block test rig. The results showed that lubricant additive PTFE can decrease the friction coefficient and consequently improved the wear resistance of PEEK under seawater lubrication, especially when the volume fraction of PTFE was about 20%. It was also found that the incorporation of CF can further improve the wear resistance of PEEK blended with 20% PTFE, especially under high load and high sliding speed. This suggested that a synergistic effect on improving the wear resistance of PEEK existed between PTFE and CF, which originated from good lubrication of PTFE, good reinforcement of CF, and good interfacial combination between CF and PEEK-20%PTFE. However, two other reinforcement additives of GF and bronze powder had an antagonistic effect but not a synergetic effect with PTFE; that is, the incorporation of the two additives greatly deteriorated the wear resistance of PEEK blended with 20% PTFE.