Ferrous metals

Iron and steel are thermodynamically unstable and revert to their oxide form in the presence of oxygen and water. The oxide form is generally known as rust.

A chemical environment will accelerate the corrosion process. Iron and steel react with aqueous acid radicals to form chloride and sulphate ions which are more corrosive than the oxide form. Once the ion-formation process has started it is self-generating. The environment in which exposure occurs has a profound effect on the corrosion rate of steel and needs to be carefully considered.

Preventing the corrosion of steel demands a multi-disciplined approach and should be considered at the start of a project rather than waiting for the structure to be completed and then asking "What do we paint it with?"