DiFruscia Industries anodizes aluminum to MIL-A-8625 (MIL-A-8625F / MIL-PRF-8625), Type II and Type III, under Nadcap accreditation for chemical processing (AC7108) and an AS9100D quality system. Every order ships with a Certificate of Conformance.

Types and classes

Type II: sulfuric acid anodize, for color and corrosion protection. See Type II – Sulfuric.
Type III: hardcoat anodize, for wear and durability. See Type III – Hardcoat and Type III with PTFE.
Class 1: undyed. Class 2: dyed. Colors: DFI’s Color Chart.

Type II and Type III at a glance

Property	Type II	Type III (hardcoat)
Typical thickness	0.0001″–0.001″ (0.0005″ minimum for dyed color)	0.0005″–0.0033″ (maximum depends on alloy)
Corrosion resistance	336 hrs salt spray (ASTM B117)	1,000–2,000 hrs salt spray, sealed
Wear resistance	Good · 15.4 mg Taber loss	Excellent · 3.4 mg Taber loss
Electrical	Non-conductive, good dielectric	Non-conductive, excellent dielectric
Appearance	Clear or dyed in a wide range of colors	Natural gray to dark bronze; can be dyed black
Growth / penetration	35% / 65%	50% / 50%
Best for	Cosmetic parts, color coding, corrosion protection	Wear surfaces, sliding parts, harsh environments

How to call it out on the drawing

Type, class and thickness. For example: MIL-A-8625, Type III, Class 1, 0.002″ ± 0.0005″.
Allow for build-up. On Type III, about half the thickness adds to each surface, so a diameter grows by about one coating thickness.
Break sharp edges. Coatings thin out and can crack at sharp corners. A generous edge radius improves hardcoat performance.
Show masked areas. Threads, bores, bearing fits and electrical contact points can be protected. See Precision Masking.
Specify the seal. Sealing closes the pores for corrosion resistance. Unsealed hardcoat is used where maximum wear resistance or bonding is needed.

Alloy matters

Color, maximum thickness and appearance all depend on the alloy. 6000-series alloys such as 6061 and 6063 anodize well for both cosmetic and hardcoat work. High-copper 2000-series alloys are hard to hardcoat, and 7000-series alloys tend toward a yellow or bronze tone. Keep an assembly to one alloy: different alloys anodize to different colors and thicknesses in the same tank.

Alloy	Recommended maximum hardcoat
2024	0.0015″ (release of liability required)
5052	0.0028″
6061	0.0020″ (T6) · 0.0025″ (T651)
6063	0.0033″
7075	0.0033″

Testing and paperwork

DFI’s in-house lab checks bath chemistry daily and runs salt spray, Taber wear, adhesion and coating-thickness tests. Coating thickness is verified to your drawing, and each order ships with a Certificate of Conformance and a packing list. Current certificates: Certifications & Approvals.

Get a quote or a data sheet

Send the drawing and the spec callout to rfq@difruscia.com, or use Request a Quote. DFI’s technical data sheet for this process is available on request from Technical Specifications. Questions: 401.943.9900 or support@difruscia.com.

Values shown are typical results for reference only and are not specification limits. Results vary with alloy, part geometry, thickness and process parameters. Contact DFI to confirm the requirements for your application.

MIL-A-8625 Anodizing: Type II and Type III