The critical effect of rust layers on localised corrosion of steel exposed to waterline environments

Waterline corrosion is a complex localised corrosion phenomenon affecting numerous engineering structures exposed to multiphase liquid-air interfacial conditions. This paper reports a new finding on the significant effects of rust layers on waterline corrosion. It was revealed that when rust layers were formed on or removed from steel surfaces, waterline corrosion behaviour changed significantly suggesting critical roles of rust layers in the kinetics, mechanism and control of localised corrosion under waterline conditions. This finding was facilitated by high resolution local current and polarisation data acquired using electrochemically integrated multi-electrode array probes, and has major implications for localised corrosion control.