Zinc Anodes

Another form of sacrificial anode, zinc anodes are generally used in salt water where the resistivity is often lower than other applications. Being a high voltage conductor, zinc has a greater negative electrochemical potential than other similar metals when it is placed into salt water. This means current will flow at a higher rate through zinc than it does the other metals when subject to this same environment, therefore, limiting electrolysis to zinc alone. In essence, the zinc stops the oxidation reaction happening at the protected metal surface as the zinc is corroded in its place.

This means that in certain situations zinc is far and away the best option as a sacrificial anode, notably when it is docked or anchored in seawater for long periods of time. In practice, zinc anodes are often positioned near and connected to the metallic components of a marine vessel that require protection from electrolysis-caused corrosion found in sea water usage, meaning they are typically used in the protection of ship hulls, boat propellers and rudders, shafts, offshore pipelines and production platforms.