Anodizing

Anodizing, electrolytic method of producing a corrosion-resistant or decorative layer of oxide on a metal, usually aluminum. The metal to be coated is used as an anode (positive pole), suspended in an electrolyte (usually an aqueous solution of sulfuric, chromic, or oxalic acid). When an electric current is passed through this solution, a coating of oxide builds up on the anode.

See also: Electrolysis.