Hardcoat Aluminum Anodizing: Extreme Durability for Demanding Applications

Metal Finishing Group provides Hardcoat Anodizing, often referred to as “Type III anodizing” per the MIL-A-8625 specification. This electrochemical process precisely controls the oxidation of an aluminum surface, forming an exceptionally durable oxide film. Hardcoat Anodizing uses sulfuric acid baths kept at low temperatures, combined with high voltage, to achieve a very high surface hardness, typically ranging from 60-70 Rockwell C.

Hardcoat Anodizing is the preferred choice for applications requiring superior corrosion, abrasion, and wear resistance. The appearance of the coating can vary from light to dark gray, depending on the specific aluminum alloy, and it can also be dyed black. Parts can be processed with multiple finishes, such as a combination of Hardcoat and Chem Film.

It is important for engineers to note that the oxide film created by the anodizing process penetrates into the base material at a rate nearly equivalent to its surface growth. For instance, a total film thickness of 0.002 inches will result in a dimensional change of 0.001 inches. Hardcoat anodizing can lower the fatigue strength of aluminum. For applications where stress is a primary concern, chromic acid anodizing (MIL-A-8625 Type I) or thin film sulfuric acid anodizing (MIL-A-8625 Type IIB) should be considered instead of hardcoat anodizing.

Properties of Hardcoat Anodizing:

Hardcoat Anodizing imparts a range of beneficial properties for challenging environments:

  • Adhesive Compatibility: The coating is compatible with various adhesives, allowing for strong bonding.
  • Lubricity: The hardcoat layer provides excellent lubricity, reducing friction and wear.
  • Corrosion Resistance: It offers strong resistance to marine and atmospheric corrosion.
  • High Operating Temperatures: The coating maintains its integrity even at elevated operating temperatures.
  • Electrical Resistance: The film provides significant electrical resistance.
  • Galvanic Neutrality: Hardcoat anodizing helps prevent galvanic corrosion that can occur when dissimilar metals interact.

Metal Finishing Group’s Hardcoat Anodizing Capabilities:

We offer robust Hardcoat Anodizing services with precise control over film characteristics:

  • Thickness Ranges: We achieve thicknesses from 0.0001 inches to 0.0030 inches. Please remember that anodizing thickness involves approximately 50% build and 50% penetration into the substrate; this must be factored into pre-anodize machining tolerances.
  • Rack and Bulk Processing: We efficiently handle both rack and bulk processing for various part sizes and volumes.
  • Precision Masking for Selective Anodizing: We offer precise masking services to ensure only specified areas of a part are anodized.
  • In-house Quality Testing: We perform in-house salt spray testing per ASTM B 117, coating weight analysis, and Taber abrasion testing to verify coating performance.
  • Post Anodize Seals: Post anodize seals are available for increased corrosion resistance, though they may slightly reduce surface hardness.
  • Masking for Multiple Finishes: We can utilize Type I and Type II anodizing as masking agents for parts requiring multiple finishes.

Applicable Anodizing Specifications:

Our Hardcoat Anodizing processes consistently meet or exceed crucial industry specifications:

  • MIL-A-8625F Type III
  • ASTM B580 (Type A)
  • CP-1000 (UTAS)
  • MIL-STD-171
  • AMS 2468 & 2469
  • SP-222 (Woodward)
  • 580-0008 (Rockwell Collins)

Typical Hardcoat Anodizing Applications:

Hardcoat Anodizing is applied across many demanding industries:

  • Aerospace/Astrospace/Aviation: Provides wear resistance, dry lubrication, longevity, and electrical insulation for critical components.
  • Firearms: Offers corrosion and wear resistance for components like AR-15 upper receivers and hand guards.
  • Machinery: Enhances abrasion resistance for high-speed machine parts.
  • Electronics: Delivers uniform emissivity and a high dielectric for electronic components.
  • Oil and Petrochemical: Provides vital corrosion protection and wear resistance in harsh environments.
  • Ordnance: Ensures corrosion protection, abrasion resistance, and wear resistance.
  • Cookware: Improves corrosion protection and offers non-stick properties.
  • Molds and Dies: Leads to improved release properties and abrasion resistance.
  • Sporting Goods: Contributes to enhanced durability and performance.

Why Choose Metal Finishing Group for Hardcoat Aluminum Anodizing?

Metal Finishing Group is a trusted partner for robust Hardcoat Aluminum Anodizing. Our dedication to quality control and adherence to precise specifications deliver an exceptionally hard and durable finish. Partner with us for a surface solution that stands up to the toughest challenges, extending the life and performance of your aluminum parts.