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Is there a good substitute for Chromic Anodizing?

I work in Aerospace manufacturing, and I keep hearing from my vendors that Chromic Anodizing is on its way out. They are also having problems finding Anodizing resources that will do the Chromic Anodizing process. Can anyone tell me if that is valid? Is Chromic Anodizing becoming unavailable? Is there a good substitute for Chromic Anodizing?
Thank you,

Steve St. Jacque
Aerospace Manufacturing - St. Paul, MN, USA
May 15, 2008

Look into the "Boeing" process. It is a sulfuric acid/boric acid process that some companies accept as a substitute for some parts.

James Watts
- Navarre, Florida
May 16, 2008

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May 19, 2008

Steve,

Big subject at the moment, how to remove hexavalent chrome from the workplace.

As far as I am aware there is no specific legislation, either side of the pond, that actually bans the use of chromic acid but the rules on the use of the substance are being tightened to such an extent that it becomes very restrictive to use. The cut in the occupational exposure limit by the OSHA is quite onerous, in Europe there are whole bodies of legislation restricting where you can use hexavalent chromes such as ELV, RoHS, WEEE and watch out for REACh, the next big one to push production out of Europe.

As for alternatives you could look at phosphoric acid anodising for bonding key, thin film sulfuric anodising for paint key or corrosion resistance or you could look at one of the modified sulfuric anodises such as sulfuric/oxalic. It really depends on what you want the anodising to do for you.

Brian Terry
Aerospace - Yeovil, Somerset, UK

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