Hard coat anodized aluminum
Hard coat anodizing is a method of anodizing aluminum. Anodizing is an electrochemical process that converts surface aluminum to aluminum-oxide. Anodizing improves the metals resistance to corrosion, wear and increases durability. Hard coat anodizing further enhances these properties.
Anodizing is designated as Type I or Type II. Hardcoat anodizing is referred to as Type III anodizing.
Hard anodizing or hard coating uses a sulfuric acid electrolyte to convert the aluminum surface to aluminum oxide. The sulfuric acid bath is approximately 32 degrees F, with a current density of 23 to 37 amps. The time to hard coat is from approximately 20 minutes to 2 hours. The alloy and coating thickness determines the amount of time.