Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Will aluminum withstand caustic environment?
We have a customer who has a corrosive environment that contains 26-degree Baumé Ammonium Hydroxide at a nominal temperature of 155 °F.
He currently is using a finished enclosure of galvanized steel that is not giving him satisfactory service. What he wants to know is if an anodized aluminum finish will withstand this corrosive environment. His alternative is a stainless steel substrate.
Will anodized aluminum withstand this environment?
Thanks,
anodizing shop - Philadelphia, Pennsylvania
1996
Treatment &
Finishing of
Aluminium and
Its Alloys"
by Wernick, Pinner
& Sheasby
(note: this book is two volumes)
on eBay or
AbeBooks
or Amazon
(affil links)
I don't quite understand, Joe. Is this enclosure actually a container for the ammonia
⇦this on
eBay or
Amazon [affil links] water, or is the enclosure merely in a room where vapors from the process are present? Is it the room that is 155 deg., or is it the liquid?
Aluminum is unacceptable for caustic immersion service (it doesn't even hold up long in a dishwasher), so with or without an anodized surface I wouldn't consider it. But anhydrous ammonia has only a moderate effect on aluminum, so if it's only dry vapors, anodized aluminum would probably be okay. Now, if the case is halfway in between, with splashing or very high humidity, you are back into a questionable area, but personally I don't think it would be a very good application for an anodized finish.
Note that this is only a projection from book knowledge--so if anybody out there has 'hands-on' knowledge, please chime in!
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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