52011

How to passivate aluminum with acid?  

April 27, 2009

I need to passivate bare aluminum for my project. Is there any simple way to do that? Such as immerse the aluminum bar into high concentration acid like sulfuric acid or nitric acid? Please help and thanks a lot!!!!!^_^

Jie Li
product designer - Hatfield, PA & U.S.A.

Hello, Jie. The word "passivate" is a bit troublesome because aluminum cannot be passivated in the same sense as stainless steel; but it can be passivated in the same sense as zinc plating, i.e., with a chromate conversion coating.

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Yes, oftentimes one must be specific about what is meant by "passivation".

If the goal is simply to remove any surface contaminant iron that may have been deposited during machining and tooling, stainless steel passivation procedures apply. This can be done quite easily with citric acid. Let us know if we can help.

Ray Kremer Stellar Solutions, Inc. McHenry, Illinois