What is Anodizing?

Anodizing is an electrochemical process that converts the metal surface into an oxide finish.  At Verdun Anodizing, we treat only aluminum even though nonferrous metals, such as magnesium and titanium, also can be anodized.


The objectives of anodizing are to form a layer of aluminum oxide surrounding the part to protect the substrate against corrosion, fatigue, and in some cases, giving a better decorative finish. This thin oxide structure originates from the aluminum substrate and is composed entirely of aluminum oxide. The anodic layer is not applied to the surface like paint or plating, it is fully integrated with the underlying aluminum substrate. This layer is a highly ordered and porous structure, and allows a secondary process such as coloring and sealing.


Anodizing is accomplished by immersing the aluminum into an acid electrolyte bath and passing an electric current through the medium. At the contact point where the current passes, there will be no anodizing.  Our professionals will minimise the contact points and place them,  if we can, in areas you  .  Prior to anodizing, there is some pre-treatment as cleaning and etching and deoxidizing.


Type of anodizing at Verdun anodizing:

  • Type I-Chromic Acid Anodize,
  • Type II-Sulfuric Acid Anodize,
  • Type III Hard Anodize,
  • BSAA Boric Sulfuric acid anodizing


Sealing solution

  • Deionised water sealing solution
    • Using hot DI water to close pores
  • Dichromate seal
    • Using hexavalent chrome solution to fill pores providing maximum corrosion resistance
  • Dilute dichromate seal    
    • Using dilute hexavalent chrome solution to improve corrosion resistance and providing excellent paint adhesion.

 Teflon impregnation os also offert after hard anodizing to improve lubricity.