Hard Anodizing

Hardcoat Anodize or simply Hard Anodize is a dense anodic coating of aluminum oxide applied by converting a properly cleaned and deoxidized aluminum alloy component into an oxide film using a suitable electrolyte, typically sulfuric acid cooled to nearly freezing, and applied voltages upwards of 100 volts at an applied current density of 24-36 amps per square foot.

Hardcoat Anodize is Type III which is done under more exacting process conditions resulting in a harder, denser, thicker, and more abrasion resistant coating.  Hardcoat thicknesses can vary from 0.0005 to 0.0030” and beyond but is dependent on the specific alloy being anodized.

Hard Anodize Features:

• Improved wear resistance
• Non-conductive
• Can repair worn surfaces on aluminum
• Improve parts surface for slide applications
• Can be black dyed; other colors less decorative
• Finish is harder than tool steel
• Can be ground or lapped

What are the governing specifications that cover Hardcoat Anodize?

• MIL-A-8625, Type III
• MIL-PRF-8625, Type III
• AMS 2469
• ASTM B580, Type A
• ISO 10074 
• MIL-A-63576 ( PTFE Sealed )
• AMS 2482 ( PTFE Sealed )