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Type III Hard Coat Anodizing

Type III Hardcoat Anodize for Advanced Manufacturers

Type III Hardcoat Anodizing, also called Hard Anodize, is a highly abrasion resistant/non-conductive coating that makes an aluminum surface harder than tool steel due to greater thickness & weight than conventional Type II Sulfuric Anodizing.

In general, Hardcoat Anodizing is ideal for commercial and consumer applications where the need for surface hardness and abrasion resistance are the main criteria. More specifically, Hard Anodize is specified for aluminum components subject to extreme wear, applications where superior abrasion resistance is needed, and/or for corrosive environments where a thicker, harder, more durable coating is necessary. Hardcoat Anodize can also be valuable where enhanced electrical insulation is required.

AOTCO finishes for a variety of common specs and also plates to ASTM 2482 (Hardcoat with Teflon Impregnation).

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Hardcoat Anodizing

Hardcoat Anodizing also uses sulfuric acid but creates a much thicker coating for the metal. The surface is hard and durable, meaning it’s perfect for heavy use. Hardcoat Anodizing are non-conductive, meaning that it’s excellent for electrical insulation. The thickness of the coating means it can also be used to fix worn aluminum components.

Frequently Asked Questions

Type III Hardcoat Anodize Properties & Benefits
  • Coating Thickness: ~ .0005 to .0045 inches, depending on specs/process or alloy
    • Anodize Coating Thickness is surface penetration plus surface build-up
    • If coating is not specified on contract or applicable blue prints, the nominal Hardcoat thickness shall be .002”
  • Substrates: A wide variety of aluminum alloys
    • Including 1100, 2000, 3000, 5000, 6000, and 7000 series alloys
  • Benefits:
    • Corrosion protection
    • Abrasion resistance
    • Improved durability and wear resistance o Increased hardness (harder than tool steel)
    • Improved surface for slide applications
    • Improved thermal insulation
    • Non-conductive
    • Can repair worn surfaces on aluminum (useful for salvaging worn or mis-machined components)
    • Color depends on the alloy and the final Hardcoat thickness
  • Please Note:
      • Wear resistance is reduced by sealing, so sealing of Type III coatings is not recommended unless corrosion resistance is also a factor
      • Fatigue strength can be reduced by Type III Hard Anodize
      • The build-up of thicker Hardcoat finishes can impact the final dimensions which should be taken into account
      • Thick coatings (over 0.004”) will tend to break down sharp edges.
Type III Hardcoat Anodizing Applications & Industries
  • Valves
  • Sliding parts
  • Hinge mechanisms
  • Actuating Cams
  • Gears
  • Hydraulic cylinders
  • Swivel joints
  • Pistons
  • Rocket nozzles
  • Insulation plates
  • Blast shields
  • Wear surfaces
Type III Hardcoat Anodize Specs & Certifications
  • AMS 2468 --- NADCAP Approved, ROHS Compliant
  • AMS 2469 --- NADCAP Approved, ROHS Compliant
  • AMS-A-8625 --- NADCAP Approved, ROHS Compliant
  • MIL-A-8625 --- NADCAP Approved, ROHS Compliant
  • ASTM B580
  • ASTM 2482 (Hardcoat with Teflon Impregnation) --- NADCAP Approved, ROHS Compliant
“Flash” Hard Anodizing
“Flash” Hard Anodizing may be used instead of conventional Anodizing for corrosion resistance and may be more economical in conjunction with other Hard Anodized areas.

Looking for Specs?

Learn more about the specifications AOTCO offers, including NADCAP-accredited and RoHS-compliant ones.
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