The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Does running multiple metals simultaneously upset salt spray results

Could you explain the chemical reactions between different kind of coatings & parts during Salt spray testing? I think, corrosion behaviour of a coating will be affected because of testing different kind of coated articles in same testing equipment at same time. please brief.

Thanks in advance.

R.Selvaraj
student - Coimbatore, India
2005

---

2005

Your questions are vague and confusing. You fail to give any details about the nature of the coatings, metals or chemical pretreatments that are being used here. Performance in the salt spray test is dependent on all three of these aspects.

If you want a good answer, you first need to ask a good question. ;-)

George Gorecki
- Naperville, Illinois

---

I'm mostly at fault here, George. We are trying to limit the posting of vague questions, so we normally would have requested clarification before posting Mr. Selvaraj's question. But the question that I read--and I might have misread it--was whether it is valid to test different kinds of parts in a salt spray chamber simultaneously (different coatings and/or different substrates). I assume this would distort the testing because of galvanic interactions, but I don't know for sure and was hoping to hear someone say whether it rendered the test invalid and to quote the prohibition if so.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005

I read the question the same as Ted. You should not have a galvanic reaction between dissimilar base metals in a salt spray cabinet, but it is remotely possible. That said, I would not put mixed base metals and plated metals on the same rack unless it was absolutely necessary. My tank held 4 racks, so it was not a problem to keep them separated. I would think that it would be more possible with old racks than with new ones.

James Watts
- Navarre, Florida
2005