Anodic oxidation is an electrochemical method for the production of an oxide film on a metallic substrate. It removes electrons from a substance and oxidizes the anode.
Anodic oxidation increases corrosion resistance and wear resistance, and provides better adhesion for paint primers and glues than does bare metal.
Anodic films 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.