-- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing

on this site
current topics
topic 0314

Will aluminum withstand caustic environment?

adv.   automatic anodizing banner

A discussion started in 1996.
Add your Q. or A. to restore it to the "Current Topics" discussions.


We have a customer who has a corrosive environment that contains 26-degree Baumé Ammonium Hydroxide at a nominal temperature of 155 degrees 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?


Joe Hillock
anodizing shop - Philadelphia, Pennsylvania

Surface Treatment & Finishing of Aluminium and Its Alloys
Wernick, Pinner & Sheasby
from Abe Books


I don't quite understand, Joe. Is this enclosure actually a container for the ammonia 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, Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey

This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site


Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2018, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.