Electrochemical noise studies on complex galvanic corrosion of submarine cable armor layer in artificial seawater

Abstract

This paper aims at studying the complex galvanic corrosion of galvanized steel/red copper of submarine cable armor layer in simulated seawater environments. The variation of the galvanic corrosion rate of the cable armor layer as a function of time under different environmental factors (pH, [Cl−], dissolved oxygen, etc.) has been explored. The surface morphology of the galvanized steel after galvanic corrosion was observed by scanning electron microscopy. The results indicate that galvanized steel and red copper are susceptible to galvanic corrosion when ohmically coupled in NaCl solution. Red copper, with the more positive electromotive potential, acts as the cathode in the galvanized steel/red copper galvanic couple and accelerates the corrosion of the galvanized steel. The galvanic effect of red copper on galvanized steel in NaCl solution increases with the increasing [H+] and dissolved oxygen. However, with increasing [Cl−], the galvanic effect of red copper on galvanized steel initially increases but then decreases, resulting in a maximum in the corrosion rate.