Sulfuric Type III Class 1 and 2 Finishes Undyed and Dyed Black

Hard anodizing is an electrochemical process in which the surface of aluminum can be thickened and toughened by the anodize. The anodize coating is a protective oxide which is a thicker coating than what occurs naturally. By improving its abrasion resistance, the resulting finish, depending on the particular type of anodizing can be the second hardest substance know to man, second only to the diamond. The resulting coating becomes part of the metal. The porous structure of the coating allows secondary infusions of organic and inorganic dyeing, lubrication aids, waxes, etc.

Developed in the early 1930ís, anodizing greatly extends the life of the aluminum, therefore, allowing its use in products where the metal might not have otherwise been utilized.

Anodizing also can alter and improve the aluminumís appearance by using dyes and special anodizing procedures. The finish can make aluminum look like pewter, stainless steel, copper or brushed bronze.

Key Benefits

Hard anodizing is used for several reasons. First, it improves corrosion resistance by speeding up the naturally occurring oxidation process, especially in environments where the aluminum will be exposed to industrial, humid, and marine atmospheres. Second, the anodizing finish provides excellent electrical insulating properties when dielectric properties are important for electrical components. Third, anodized aluminum is easy to clean and resists heat to the temperatures to which the aluminum itself melts. Fourth, the appearance of the aluminum which is hard anodized can be changed through the use of a black dye allowing aluminum parts to be color coded and matched to painted components for a uniform appearance. Fifth, anodized aluminum allows for excellent abrasion resistance, therefore improving the life of the aluminum in high-abrasive environments where aluminum components are subject to the extremes of friction. And sixth, anodizing can improve paint adhesion. Though less expensive coatings can provide similar improvements, the process provides for excellent adhesion.


  Improves corrosion resistance.  
  Provides electrical insulation.  
  Resists high temperature extremes.  
  Improves appearance.  
  Provides paint adhesion.  


Good for all types of aluminum alloys.

Anywhere aluminum can be used.

  Military products.  
  Industrial products.  
  Commercial products.  
  Consumer products.  
  Automotive products.  

Most commonly used military standard MIL-A-8625.

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