What Is the Anodizing Process?

Cleaning and Etching

• Before anodizing, manufacturers must prepare the metal surface. They use a heated detergent bath to clean the surface of impurities, then rinse the surface multiple times with water. A caustic soda then etches the surface, followed by an acidic rinse.

Anodizing

• According to the Engineer's Handbook, anodizing occurs in a tank containing an electrolytic solution into which manufacturers introduce an electrical current. The tank itself acquires a positive charge and the item to be anodized a negative charge. Ions migrate to the surface of the anode, creating the protective anodized coating.

Dying and Sealing

• After anodizing, the coating is somewhat porous and can be dyed in various colors, if desired. Manufacturers then seal the coating to maximize its resistance to corrosion and other types of wear.