A widely used treatment for aluminium, anodising is a term derived from the process of anodic oxidisation, but what does that all mean, and why is it so widely used?
Diving into the GCSE DT revision guide tells us in simple terms that anodising provides metals with a protective coloured surface. This process is most successfully carried out on aluminium.
Looking at the process
Anodising usually takes place as part of an electrochemical process, which is used in order to form an oxide layer on the aluminium. The oxide layer then forms a protective coating onto the base aluminium. Uniquely, there is no additional layer applied to the aluminium as part of the anodising process. During anodising, the protective layer is made up of the existing aluminium and is therefore an integral part of the material, forming a very strong molecular compound.
As with other surface treatments, there are a range of thicknesses in which anodising can occur. As you may expect, the different thicknesses are used in different applications, with thinner layers destined for use in internal locations. Outside applications will require thicker treatments. In the opinion of experts such as Poetons surface treatments of thicknesses between 15 to 20 microns are recommended outside.
Benefits of using anodised aluminium
Most anodising of materials such as aluminium takes place to protect the metal. The main protections provided to materials by anodising include that against corrosion. Not only does the material resist corrosion, but it also looks better for longer. The hardy, weather resistant layer which is built up by the anodising process provides a very credible protection, giving it great durability when used in construction.
That said, anodising does not just provide benefits in terms of protection. Anodising is a process which also provides a decorative value to aluminium. It is possible to anodise metals in order to give them particular colours, with other pre-treatments available to further enhance the decorative appeal of a material.
Keep it clean
In order to retain the benefits of anodised aluminium, it is vital to be very careful when cleaning. Use of pH neutral cleaning products is vital, as harsh detergents will affect the finish. The low maintenance nature of the finish means that in outside environments away from heavy industry, a single clean up per year is all that is necessary.