Anodising is an electrolytic process for producing thick coatings, usually on aluminium and its alloys. The oxide layer is typically 5 to 30 microns in thickness and is used to give improved surface resistance to wear and corrosion, or as a decorative layer.
In the electrolytic process, the component to be treated are made an anode in a dilute acid solution. Oxidation occurs at the component surface, resulting in the formation of a coherent oxide film. This provides better adhesion for paint primers and glue compared to bare metal.
Anodic film can also be used for a number of cosmetic effects, either with thick porous coatings that can absorb dyes or with thin transparent coatings that add interference effects to reflected light.
Splash effects can also be obtained by blanking off parts of the component after the first colour and then adding a second or third colour.
