3 Types of Anodizing
Type 1: Chromic Acid Anodizing
Chromic Acid anodizing is a metal coating process used when the application calls for a thin coating and a high level of corrosion resistance. Type I coating is achieved by a chemical conversion processes involving immersion of an aluminum component in a chromic acid bath.
Type 2: Sulfuric or Color Anodizing
The process essentially speeds up the natural oxidation of aluminum by placing an object into a bath of sulfuric acid and running an electric current through the solution. Dyed anodizing is usually sealed to reduce or eliminate dye bleed out.
Type 3: Hardcoat Anodizing
Type III (Hardcoat) anodizing forms a very hard, dense, and relatively thick coating. It is used whenever the application calls for a super hard surface. The process is similar to Sulfuric Anodizing, but the layer of aluminum oxide is produced at much higher voltage and cooler temperatures.