Conversion Coating (Chromic Acid/ Chem Film/ Alodine)
Chromate Conversion Coating is a chemical immersion process in which aluminum oxide and chromic oxide is produced in the outer layer of the metal. During the process, aluminum is exposed to chromic acid (as opposed to sulfuric acid) and a thin, gel-like film is produced in the surface. This accounts for an excellent pretreatment for paint or adhesives since it greatly enhances the product's ability to form a bond with the aluminum. It is frequently used on electrical and electronic equipment because it provides increased corrosion resistance while remaining electrically conductive.