Anodised aluminium is a particularly popular option, with a smooth translucent finish that showcases the alloy’s natural sheen from any angle. Its durability is legendary, with exceptional levels of inbuilt protection enabling this popular cladding material to retain its original appearance for decades. As well as being largely impervious to corrosion and the ultraviolet radiation in sunlight, anodised aluminium can’t flake or peel; at the same time, its environmental credentials are reflected in the ease with which it can be recycled.
The electrochemical technique of creating anodised aluminium requires specialist tools and expertise. This is a surface treatment rather than a coating, based on the principles of passing an electrical current between an anode and cathode. The aluminium sheet forms the anode part of this electrical circuit, with cathodes already installed within a dedicated anodising tank filled with an electrolyte solution. Passing an electrical current through this solution causes oxygen to be released at the anode, which reacts with the metal to form an oxide layer across the surface.
By leaving the aluminium within the anodising tanks for different periods of time, or introducing certain dyes and chemicals, a wide variety of colours can be generated. Despite its susceptibility to scratches and surface marks, anodised aluminium has been a favoured material among architects and builders since the 1950s. Its popularity among the construction sector shows no sign of diminishing, particularly as an alternative to painting aluminium or powder coating it.