Filing Number: PI 20090119
Aluminium alloy is used as the sacrificial anode type cathodic protection systems in which provide cathodic current by galvanic corrosion. The current is generated by metallically connecting the structure to be protected to an aluminium alloy that is electrochemically more active than the material to be protected. Aluminum itself has an equilibrium potential of -1.1 V vs. SCE and therefore thermodynamically it is a very reactive metal. However, in most natural environments aluminum has been found to be stable due to the formation of a thin protective oxide. This film has a high electrical resistance and thus renders pure aluminum useless as a sacrificial anode. But in the light of aluminum other favorable properties, including a large electrochemical equivalent, relatively low cost and low density, and attempts have been made to modify this oxide film. To disrupt the physical integrity of the protective film, small amount of the alloying element has been used to induce activation of aluminium. This aluminium alloy product is recommended for mitigating corrosion on structures that are exposed to a variety of saline environments such seawater, marine muds or brackish waters. The successful aluminum alloy anodes mainly contain zinc, magnesium with small amount of activator element. The current capacity of such alloys is in the region of 2500 A hr/kg and anode efficiencies can be greater than 90%. The product is ready for technology transfer for commercial production.