Development of impressed current cathodic protection system for corrosion prevention of ship hull

Abstract

Recently, impressed current cathodic protection (ICCP) using mixed metal oxides (MMO) has been widely applied for ship hull protection from corrosion in marine environment because of its high protection efficiency as well as high economic efficiency. In this paper, the characterization of MMO electrode materials as well as the design, fabrication, assembling, and operation of an ICCP system were reported. Stability of MMO anode was evaluated by the galvanostatic method at different current densities and concentrations of NaCl solution. The results showed that Ti/RuIrTiO₂ electrode system may be suitable to be used in ICCP system operating at high current density around 600 A/m2 in marine environment (NaCl 3.5%). Using this electrode system, a full ICCP system, including an auto control rectifier, MMO anodes, and reference electrodes was designed, fabricated and operated by Institute of Materials Science to protect the hull of ship Minh Phu 99. The collected data showed that potential of ship hull was much more negative than -800 mV (protection potential value according to cathodic protection standards), which means this ICCP system has operated well for six months.