Galvanised and sprayed steel, aluminium, copper, brass, lead etc.

Non-ferrous metals are not suitable for general structural purposes as they lack strength workability chemical resistance and cost-effectiveness of Iron and Steel. They are used in specific areas where steel is unsuitable. For example aluminium and aluminium alloys are used in fabrications, cladding etc. However although they are not suitable for structural purposes zinc aluminium and magnesium are all used as coatings in their own right to afford cathodic protection to steel.

Zinc is generally used as a metallic surface coating on steelwork where it is deposited either electrolytically or in the molten form. Both zinc and aluminium or a combination of both are used in metal spraying where steel surfaces are sprayed with molten metal. Although these metals do not rust' they do corrode. In normal situations the corrosion by-products act as a protective layer and inhibit further corrosion. However the corrosion does impair adhesion of any paint coatings subsequently applied. This is not the case in chemically polluted and marine situations where chemical corrosion attacks non-ferrous metals. These metals should not be specified in chemical environments where attacks on them are more severe than on steel.

When using non-ferrous metals the principles of corrosion prevention and design given for Ferrous Metals still apply.