Investigation on Tribocorrosion Characteristics of 316L Stainless Steel for Seawater Pumps in Seawater Desalination Systems

In this paper, tribocorrosion characteristics of 316L stainless steel were investigated. Experimental results revealed that stability of chromium oxide film under corrosion conditions led to an increase in potential and a decrease in corrosion current density. However, under tribocorrosion conditions, destruction of the oxide film by friction led to a decrease in potential and an increase in corrosion current density. This was because grain refinement and residual stress concentration on the surface caused by friction affected the electrochemical stability of the oxide film. However, under corrosion conditions after tribocorrosion experiments, the potential increased over time while the corrosion current density decreased due to reformation of the oxide film. Nevertheless, it presented a higher corrosion current density than the corrosion condition due to the influence of defects and residual stress caused by friction. Under tribocorrosion conditions, initial lubrication effect resulted in a low friction coefficient. However, after trans-passive potential, the friction coefficient increased significantly due to destruction of the oxide film. As a result, the wear track appeared to be an area where the electrochemical reaction of corrosive ions was concentrated whereas the surrounding area presented a relatively good corrosion protection effect.