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Galvanic Corrosion Between SS and Anodized Aluminium? [India]  

July 22, 2008

Can someone please have a look at the picture and tell me what kind of corrosion it could be?

This is a head assembly mounted on a RO System for Water Treatment.
The stainless steel mounting also shows corrosion.The white powdery substance might be aluminium corrosion-it goes away when wiped with abrasive pad but reappears again after some time.Is it Galvanic Corrosion?
What might be causing it and how to prevent it?
Any suggestions from the Experts shall be gratefully accepted and appreciated.
Thanks In Advance.

Ravi Rao
Mechanical Engineer - Belgaum, India

Hi, Ravi. I'm thousands of miles away, looking at pictures of a unit that I'm not familiar with, but I don't think it's corrosion. The white precipitate is around the periphery, and the closeup shows some kind of white foam. I think stuff is forced into the crevice between the cap plate and flange when this unit is under pressure and you're seeing it ooze back out.

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey