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Experiencing white rust on post-treated galvanized iron

I am observing white rust after post passivation chemical treatment on galvanized iron? What chemical etc. should I add so that the metal can stand for higher salt spray test? What about adding surfactants and organic acids. We have increased chromium concentration in the processing solution. pH of the solution is also very low.

Sofia Darshan
BDC - Bangalore, Karnataka, India
2004

I could be misunderstanding you, Sofia, but I think you are asking us to tell you how to better adjust the recipe for your home-brew chromate conversion coating without telling us your recipe. There are almost countless brands of proven proprietary chromate conversion chemistry, any one of which will probably outperform your home-brew. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
2004

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