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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Recommended Chemicals For Aluminum Etch
April 21, 2011
Hi,
Currently I'm in the midst of my evaluation to etch aluminum. Fyi, I'm trying to etch a layer of aluminum deposits from aluminum base. Have tried with KOH, Nitric acid and phosphoric acid. Etch rate with KOH is too fast, that it etches the base material too much.
But, Nitric acid and phosphoric acid etch slowly and etch both aluminum deposition and aluminum substrate at almost the same rate.
What would you recommend to etch the aluminum deposits faster than the etching of aluminum substrate. Or at least to soften the aluminum deposition so I can easily remove it by abrasive blasting afterwards.
Engineer - Malaysia
Hi, Peter.
How were these aluminum deposits deposited? Were they deposited in such a way that the deposited aluminum is chemically different than the aluminum of the substrate? If the deposited aluminum is fundamentally different, like an aluminum oxide, you might try the chromic acid / phosphoric acid mix that is used to strip anodizing. It is described in letter 2776 . Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April , 2011
April 26, 2011
Well,
If you are attempting to remove aluminium oxide the normal solution would be to employ a Hydrofluoric acid etch.
This is very nasty, dangerous stuff.
Your Enquiry is somewhat unspecific so maybe a further elaboration would help us to help you.
If you are not adequately qualified do not even try playing with Hydrofluoric.
Hope this helps,
Regards,
Bill
Trainer - Salamander Bay, Australia
April 26, 2011
Peter
If you are trying to remove flame spray / TWAS aluminum off aluminum, removing most of the deposit with blast prior to the chemical strip might be more effective.
I second the HF advisory.
- Colorado Springs, Colorado
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