What is Anodizing and How is it Performed?

Anodizing is an electrochemical means of building an aluminum oxide film on aluminum. The process consists of making the aluminum part electrically positive, or the anode, in a suitable electrolyte. The most frequently employed electrolyte is dilute sulfuric acid. Much less frequently, other electrolyte such as sulfo organic acid, chromic acid, boric acid and oxalic acid are used when dictated by specific requirements for the anodic film.

What does Anodizing accomplish?

Anodizing changes the physical and chemical charactertstics of the aluminum surface. The anodic film:

  1. renders the surface harder and more abrasion resistant.
  2. insulates the aluminum surface against passage of electricity.
  3. helps improve upon the natural corrosion resistance of aluminum.
  4. allows aluminum parts to be decoratively colored by absorbing dye into the anodic film, by a combination of alloy and process production an integral color, or by impregnation of the anodic pores with metal salts.
  5. helps to preserve the original aesthetic appearance of an aluminum part.