Anodizing is an electrochemical process that converts the metal surface into a durable, corrosion-resistant finish. Materials most commonly used in the anodizing process are:
The aluminum oxide is not applied directly to the surface like paint, but it is fully integrated with the underlying aluminum substrate. This does not allow any chipping or pealing of the part, and allows for secondary processes such as coloring or sealing.
First the aluminum or other material is immersed into an acid electrolyte bath and passes an electric current through a medium. A cathode is mounted to the inside of the anodizing tank, where the aluminum acts as an anode. The oxygen ions are released from the electrolyte to combine with the aluminum atoms at the surface of the part being anodized.