Galvanic Anode (Sacrificial Anode)

A galvanic anode is the main component of a galvanic cathodic protection (CP) system used to protect buried or submerged metallic structures from corrosion.

They are made from a metal alloy with a more “active” voltage (more negative reduction potential / more positive electrochemical potential) than the metal of the structure. The difference in potential between the two metals means that the galvanic anode corrodes, so that the anode material is consumed in preference to the structure.

The loss (or sacrifice) of the anode material gives rise to the alternative name of sacrificial anode.

There are three main metals used as galvanic anodes, Magnesium, Aluminium and Zinc. They are all available as blocks, rods, plates or extruded ribbon. Each material has advantages and disadvantages