Untreated aluminium has low wear resistance and on exposure to the environment, it naturally forms a thin aluminium oxide layer that provides protection from corrosion. But this naturally formed oxide film can erode upon reaction with other environmental elements. The answer to providing better protection lies with anodising.
Anodising is an electrochemical process that develops an oxide coating on the surface of the part. This protects the product from wear and tear while improving the aesthetics. In this process, the product to be coated acts as an anode in an electrolytic cell, hence the name.
The process is mainly associated with aluminium, many other metals are suitable for anodising. Metals such as magnesium, titanium, zirconium, niobium, zinc, hafnium, and tantalum are anodised, albeit for different purposes.
Anodising is a premium finish, compared to plating and powder coating and can achieve a variety of different finishes which are authentic to the material they are mimicking.