Anodic oxidation, also known as anodization, is an electrochemical process that transforms the surface of aluminum into aluminum oxide. Thus, the oxide layer is fixedly bonded to the aluminum and the layer thickness can be chosen within a given range. Unlike the galvanic coating process, the protective layer is not destoried on the part to be manufactured, but a transformation of the upper metal layer forms an oxide.

Aluminum alloys are anodized to increase corrosion resistance and to allow dyeing (coloring), improved lubrication, or improved adhesion. However, anodizing does not increase the strength of the aluminium object. The anodic layer is non-conductive.