Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Corrosion Protection of Aluminum

Corrosion Protection of Aluminum

Corrosion Protection of Aluminum

I am looking for a coating to protect aluminum (300 series casting and 6063-T5 extrusion) from corrosion by clorine bleach, ammonia, industrial cleaners, tap water, and bodily fluids.  Some coatings I am aware of are hard coat anodize and powder coating.  

Any recommendations or suggestions are greatly appreciated.

RE: Corrosion Protection of Aluminum

The military regularly uses ion-vapor deposited (IVD) aluminum to protect aluminum.  Cadmium is another possibility, but cadmium is a carcinogen, so you don't want to work with it unless you absolutely have to.  

Jim Treglio
Molecular Metallurgy, Inc.

RE: Corrosion Protection of Aluminum

You can also electroplate/vacuum deposition different materials (chrome, nickle, titanium, etc.) over aluminum depending on the costs you have in mind.


RE: Corrosion Protection of Aluminum

Depending on the thickness, cost, and environment you may wish to look at Physical Vapor Deposition coated ceramics.  A lower cost PVD alternative is aerosol sprayed coatings from such companies as www.zypcoatings.com and others.  To research materials go to www.matweb.com

Hope that this helps.   Ken  

RE: Corrosion Protection of Aluminum

PVD coatings can help reduce corrosion, but primarily by serving as a barrier.  If the coating has pinholes, or is scratched, the substrate will corrode, often faster than if they were uncoated due to galvanic effects.  Pure aluminum, cadmium, and zinc, on the other hand, act as sacrificial coatings.  They are more reactive than the substrate, but their oxides are stable and cling nicely to the base metal.  They protect even when the surface is scratched or there are holes in the coating.  In fact, the standard military test for these coatings is to inscribe an X in panels down to the base metal, then put them into a salt spray chamber.  When corrosion (red rust if the substrate is steel) is observed on the exposed surface, the coating is said to have failed.  With a chromate conversion coating, IVD aluminum coatings run thousands of hours before failure.  Without the chromate conversion coating, they still hold out for hundreds of hours.

Jim Treglio
Molecular Metallurgy, Inc.

RE: Corrosion Protection of Aluminum

There are also some inorganic coatings such as aluminum enamel that could be used for this application.  Aluminum enamel is a fused glass coating.

RE: Corrosion Protection of Aluminum

Thank you for the suggestions.  

Unfortunately our customers will sacrifice good corrosion protection for a lower cost product with less robust corrosion protection.  

How does the cost and performance of PVD, IVD, and inorganic coatings compare to a Class 3 Hard Anodize and powder coating?

Has anyone had any experience with ecoat (electrodeposition of a polyurethane, epoxy, or acrylic)?


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close