Sacrificial Anodes



Anodes protecting tubular piles on a pier


Sacrificial anodes are one of a number of methods used to protect underwater metal structures from corrosion.  This is often referred to as Cathodic Protection.

For example, if a piece of iron is placed into seawater an electrochemical reaction takes place and the iron will corrode by giving off electrons (oxidisation).

Iron is around -0.550 volts in seawater.

If a zinc anode is electrically connected to the piece of iron it will change the corrosion potential of the iron by giving it a negative charge.  Zinc is -1.2 volts in seawater.  The change in negative charge means the zinc anode will corrode instead of the iron, hence being called a sacrificial anode. Over time the anode will need replacing in order to maintain the negative charge which protects the iron.

Sacrificial anodes are normally constructed of zinc, magnesium or aluminium alloys and the choice of material depends upon what is being protected.

Commercial and Specialised Diving can install sacrificial anodes onto sheet piles, tubular piles, loch gates, ships and anything that comes into regular contact with salt water.

Anode welded onto sheet pile dock wall

Commercial and Specialised Diving have a wealth of experience installing sacrificial anodes on a wide variety of underwater metal structures, from metal piling to boat hulls. If you have a project that requires our assistance, please do not hesitate to give us a call on 01202 580007.