High-Purity AlumiPlate® Aluminum for Aerospace Fastener Systems
For fasteners and bushing systems that must exceed the performance limits of NAS4006, high-purity electroplated aluminum (typically >99.99% Aluminum) provides a technically superior and specification-compliant solution.
NAS4006 governs aluminum-pigmented organic coatings commonly used on high-strength steel, titanium, Inconel®, and Hastelloy® fasteners to mitigate environmental and galvanic corrosion. While effective for many applications, NAS4006 coatings have inherent limitations in temperature capability, chemical resistance, and system cleanliness.
Electroplated aluminum overcomes these limitations by replacing organic, pigmented coatings with a dense, pure metallic aluminum layer that delivers measurably higher performance in demanding environments.
Why Upgrade from NAS4006 to Electroplated Aluminum?
Superior Environmental and Chemical Resistance
Electroplated aluminum performs reliably in conditions that challenge aluminum-pigmented organic coatings, including:
- Acetic and sulfuric acid exposure
- Marine and saltwater environments
- Acid rain and industrial atmospheres
- Reactive and high-purity process environments
- Fluorine plasma and other aggressive chemistries
Significantly Higher Temperature Capability
- Sustained exposure up to 300 °C / 572 °F
- Intermittent exposure up to 400 °C / 752 °F
- 1.5–2X higher temperature performance compared to NAS4006 requirements (listed as 190 °C / 375 °F)
This makes electroplated aluminum well-suited for aerospace, propulsion, and high-temperature applications where organic binders are not acceptable.
Clean, Inorganic, Diffusion-Barrier Protection
- No organics, resins, or pigments
- No outgassing or process contamination
- Pure aluminum layer functions as a true diffusion barrier
- Excellent galvanic compatibility with aluminum structures
Specification-Ready Upgrade Path from NAS4006
To specify electroplated aluminum as a direct performance upgrade, use the following call-outs:
Applications Allowing Hexavalent Chromium Cr-6 (No Class)
Electroplate with high-purity aluminum per MIL-DTL-83488, Type II (Cr-6 conversion coating). Unless otherwise specified, coating thickness shall be 0.00002 to 0.0005 inches on all visible surfaces which can be contacted by a 0.75-inch diameter sphere.
Applications Where Cr-6 Is Prohibited (Class NC also meets No Class)
Electroplate with high-purity aluminum per MIL-DTL-83488, Type II (no Cr-6 conversion coating). Unless otherwise specified, coating thickness shall be 0.00002 to 0.0005 inches on all visible surfaces which can be contacted by a 0.75-inch diameter sphere.
Applications Requiring Bare Aluminum (Class NC also meets No Class)
For ultra-pure or high-vacuum environments where no conversion chemistry is permitted:
Electroplate with high-purity aluminum per MIL-DTL-83488, Type I (No Class / No conversion coating). Unless otherwise specified, coating thickness shall be 0.00002 to 0.0005 inches on all visible surfaces which can be contacted by a 0.75-inch diameter sphere.
For more info on conversion coatings, see our MIL-DTL-5541 page.
Engineering Support Included
Our plating engineers work directly with your design, materials, and quality teams to:
- Confirm correct call-outs
- Optimize coating thickness and conversion coatings
- Recommend friction modifiers when required
Contact us to upgrade your fastener systems from NAS4006 to high-purity electroplated aluminum and achieve superior corrosion resistance, temperature capability, and system integrity in demanding aerospace and industrial applications.