Aluminum anodizing is the electrochemical passivation process by which the surface layer of an aluminum substrate is converted into an aluminum oxide layer.

 

While a natural oxide layer can be found on aluminum, this layer is often uneven, thin, and offers poor protection.

 

The controlled application of an electrical charge in an acidic electrolytic bath results in a very regular and uniform layer that has increased durability, as well as wear and corrosion resistance. Additionally, these anodic layers can undergo secondary processing to incorporate various functional materials such as colorants or lubricants.