Metal Finishing – Plating & Coating
Anodizing
Controlled oxide layer on aluminum; hardness, corrosion resistance and pre-paint surface preparation. Chromic, sulfuric and hard types, with color options.
Process
An oxide-based protective layer formed electrochemically on aluminum (anodic oxidation). Applied in three types: chromic acid (pre-paint adhesion, aerospace), sulfuric acid (decorative + corrosion), hard anodize (surface hardness + wear). Black, red, blue and yellow color options.
What it provides
- Corrosion resistance
- Insulating surface
- Surface hardness and wear resistance
- Pre-paint adhesion performance
Frequently asked questions
How do I choose between chromic, sulphuric and hard anodizing?
Chromic acid (Type I) is thin, preserves fatigue strength and is used under paint on aerospace parts. Sulphuric acid (Type II) is for decorative and general corrosion protection and can be dyed. Hard anodizing (Type III) gives 25–75 µm of wear resistance. MIL-A-8625 defines all three.
Is the anodized layer sealed?
Yes. Hot water, nickel acetate or dichromate sealing is applied to specification; surfaces to be painted are left unsealed.
Have a drawing for this process?
Send your technical drawing or 3D CAD model through our secure channel. Our engineering team replies with a quotation against the specification.