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Hard Coat Anodizing

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Hard coat anodizing (or hardcoat anodizing) is a type of surface treatment used to increase wear and corrosion resistance, increase surface hardness, and improve the thermal and dielectric properties of treated aluminum objects. This process is also known as Type III aluminum anodizing. Standard (non-hard coat) aluminum anodizing is Type II anodizing. The hardcoat anodizing process is very similar to that used in standard anodizing. Both involve carefully controlled electro-chemical processes and produce similar results. However, hard coat anodizing is more of a “heavy duty” method of anodizing than Type II. Hard coat anodizing converts the surface of a treated aluminum object into aluminum oxide, forming a protective anodic film. Though aluminum passivates naturally when exposed to oxygen, the resulting oxide layer is generally only roughly two to three nanometers in thickness; aluminum alloys can form natural oxide layers up to 15 nanometers thick. Hardcoat anodizing can create significantly thicker oxide layers, up to 50 micrometers in thickness (1 micrometer = 1000 nanometers). Through careful adjustments to the anodizing process, oxide layer thickness can be customized to provide ideal protection for the treated object’s application.


Hard coat anodizing provides a number of performance and aesthetical benefits, including:
  • Greater wear resistance
  • Greater corrosion resistance
  • Greater abrasion resistance
  • Improved surface finish quality
  • Improved dielectric properties
  • Improved bond strength with coatings and adhesives
  • Can be dyed in a range of colors

Hardcoat Anodizing Providers:

  • DCHN provides full service