Tribocorrosion Behaviors of Inconel 625 Alloy Sliding against 316 Steel in Seawater

Passive alloys require not only high resistance to corrosion but also excellent tribological properties for seawater equipment applications. In this research, the tribocorrosion behaviors of Inconel 625 alloy sliding against 316 stainless steel were investigated using a ring-on-block test rig in artificial seawater and distilled water. The results showed that the friction coefficients were larger for sliding in distilled water as compared to seawater. However, the wear loss of Inconel 625 and 316 steel alloys was lower for sliding in distilled water than that in seawater. Interestingly, the corrosion of seawater obviously accelerated the wear. Moreover, with the increase of normal load, the wear loss increased but the average friction coefficient decreased in both aqueous media. The synergistic effect between wear and corrosion was significant, due to the mechanical removal of passive film. Seawater salinity does significantly influence the friction coefficient and wear loss. The Inconel 625 alloy has a maximum corrosion rate in 3% seawater, which is due to the synergism of salt concentration and dissolved oxygen in seawater. The high corrosion rate accelerated the wear loss but decreased the friction coefficients.