ABSTRACT
Aluminium alloys are normally selected for engineering applications as they have advantages in terms of low density, a high strength-to-weight ratio, high thermal conductivity, acceptable weldability, and, depending on the alloy, good corrosion behaviour in seawater. The common nomenclature system for aluminium alloys is the one devised by the Aluminium Association and uses the first digit of a four-digit number to define the basic alloy type. Aluminium alloys are favoured for uses for which their high strength-to-weight ratio, as well as a high corrosion resistance, are particular advantages. Aluminium alloys in normal use corrode either by a mechanism involving general attack, or by a localised mechanism. Certain microorganisms can become attached to aluminium alloys from seawater or from contaminated fuel and give rise to slimy biofilms on the surface. Although bare aluminium alloy surfaces can develop a good protective patina after exposure to seawater, organic coatings can be applied to produce a physical barrier between the aluminium and its environment.
