Zinc anodes has been used as a sacrificial anode material in seawater since 1824, when Sir Humphery Davy used zinc blocks to prevent corrosion of the copper cladding on the hulls of British
warships.
Modern zinc anodes used for cathodic protection are cast from high purity zinc (99.995 %) alloyed with-aluminium and silicon to combat impurities and cadmium to give uniform dissolution with loose
dispersibl corrosion products.