The history of using certain metals to galvanically protect other metals from corrosion by Sir Humphrey Davy and his pupil Michael Faraday is well known. Here, the aim was to protect ships in salt water. As time progressed protecting steel in the ground or water has become routine using galvanic anodes, and three galvanic anode material alloys have become dominant. These are zinc, aluminium and magnesium. These materials are typically very pure or have alloying additions. In all these types, the main objective of these additions or the high purity is to prevent the 50formation of an oxide film which is stable enough to hamper the dissolution of the metal, and hence reduce its current output.