During sulfuric anodizing, no metallics are involved other than aluminum. Unlike electro-deposited metallic plating, where plating builds up by depositing on a base metal, an anodic coating penetrates and grows on the base metal by converting aluminum to aluminum oxide.
Proper formation of the aluminum oxide coating provides the aluminum surface with an increased resistance to corrosion and abrasion. Depending on the anodizing type and the aluminum alloy, the thickness of the anodized layer can range from .0002” to .003”. Dyes can be deposited into the pores of the anodized layer and then sealed. The result is a highly desirable, rich, and intense color finish