Comparison of waterline corrosion of a weathering steel in static and dynamic simulated seawater

Abstract Waterline corrosion behavior of a weathering steel in static and dynamic simulated seawater was studied by means of wire beam electrode (WBE), scanning electron microscopy, and Fourier transform infrared spectroscopy in this paper. The results show that the distribution of cathode and anode on WBE surface was relatively stable under static condition with large cathode and anode structure. The region near the waterline was always a stable cathode, and the total anode current density decreased with time and basically stabilized after 6 days. Under dynamic condition, a large anode structure was formed on the WBE surface within 1 day, and the anodic current density rapidly decreased with time. The anode area gradually decreased and the WBE surface showed an alternating distribution of small anode and cathode after 3 days. The total anodic current density continued to decrease with time after 6 days. Under dynamic condition, the mass transfer of oxygen and other substances related to electrode reactions was accelerated, so that the anode surface was rapidly corroded in the early stage of immersion and covered by denser corrosion products, resulting in a positive shift in the potential and electrode reversal of some anode areas in the later stage.