Effects of Zinc and Magnesium Addition on Aluminium Sacrificial Anode: Advantages of Using Aluminium-based Sacrificial Anode in Seawater

Many elements have been used as sacrificial anodes in protecting mild steel in seawater; such elements include magnesium and zinc. The disadvantages of using magnesium and zinc as compared to Aluminium is that: they have low current conductivity, wastefully consumed in chloride environment, and supply small number of electrons per unit mass. With these advantages of aluminium over other metals as sacrificial anode, aluminium has the problem of forming a passive film on its surface in chloride environment and this prevents direct contact between the metal and its environment. Many researches have been carried out on aluminium based sacrificial anode, but the theoretical current carrying capacity of the anode is inadequate; where many where using the theoretical current carrying capacity of pure aluminium instead of the alloy produced. In addition, traditional reference electrodes used for electrochemical measurements, such as the calomel and silver/silver chloride electrodes, have a limited range of applicability compared to platinum electrode. This research aimed at investigating the optimum addition of zinc and magnesium that will give the best efficiency and polarized potential