Suitability of aluminium alloy AA5083 in marine environments

Aluminium alloys are being increasingly utilised in marine environments. Their excellent corrosion resistance combined with an excellent weight to strength ratio makes them highly attractive for structural applications. Aluminium alloy 5083 is an attractive material for marine applications. These alloys produce very low corrosion rates in marine water. However, they are prone to pitting when there is insufficient oxidiser or oxygen. Anodising has been found to reduce pitting damage but this requires maintenance every 9 months. Cathodic or anodic protection, as per AS2832.3- 2005, will provide good protection against general, pitting and crevice corrosion. Painting aluminium structures has been found to be not very beneficial to corrosion resistance unless it has sufficient thickness and maintained regularly. Structures for marine environments need to be modular in construction and be easily replaceable if there is a need.