Zn or Al-Zn-In sacrificial anodes are commonly used to protect
submerged marine structures from general corrosion and galvanic corrosion. However, such electronegative alloys can also induce stress
corrosion cracking or hydrogen embrittlement on high strength steels. Decreasing the electronegative potential applied to the structure, in the suitable range (around -0.80 V vs.Ag/AgCI) can significantly reduce the
amount of hydrogen produced by the cathodic reaction and thus limit the risk of hydrogen embrittlement. The present work has consisted in determining the criteria for a new cathodic protection system with low voltage anodes and selecting one anode that matches the determined requirements, on the basis of laboratory tests. Among the various alloys tested the Al-0.1% Ga anode provided the most promising results and therefore was selected. The first full scale marine tests performed on an industrial casting of this anode have shown the effectiveness of the Al-0.1% Ga anode in the chosen potential range, with a satisfactory galvanic efliciency in real environments.
Key Words : Low voltage anodes, Sacrificial anodes, Aluminum anode, Cathodic protection, High strength steel, Stress corrosion cracking