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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White chalk like appearance on aluminium cargo containers
Hi
Can you please explain to the uneducated why we sometimes see a white chalk like appearance on aluminium?
(In this case the floors on refrigerated shipping containers)
natural atmospheric conditions or aggressive cargos?
Thank you!
shipping - New Zealand
February 24, 2009
First of three simultaneous responses --
I would would guess that the anodize layer had been compromised, and the raw aluminum is being attacked by the marine environment
George Brackett III- Saco, Maine
February 25, 2009
Second of three simultaneous responses --
Any number of reasons. Oxygen with a wet then dry floor might do it. Spilled material that was not neutral could cause etching. Temperature cycling may have an effect.
James Watts- Navarre, Florida
February 25, 2009
Third of three simultaneous responses --
Most aluminum corrosion compounds are white. Natural occurring aluminum oxide accelerated by condensation and salt air forms a white corrosion product. Powder coat is the best protection for the salt, chloride, varying temp exposure.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
February 26, 2009
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