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citric acid passivation gel?

Dear all;
There is great discussion going on about citric acid passivation. I don't have any data in favor or again, but as a corrosion engineer, I think citric acid can be a better option.
Passive film forms automatically in favorable conditions, so if the surface is clean, there should not be any problem.
So depending on the situation, if precleaning has been done then a mild oxident or a chelator can work very well.

I want to know passivation by applying citric acid gel; Can anyone guide me, that when we use a citric paste, at what temperature we should use it and how to make the temp continuous for 20~30 minutes//...
Thanks

Dr Ihsan Toor
SHI - Korea South
March 27, 2008

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Time and temp -wise, a citric gel isn't all that different from a citric bath. The usual room temperature time is 20-25 minutes. Less if heated, but heat is less practical with the gel than with a bath so many people don't bother.

In fact heat can sometimes be a detriment, if the citric gel dries then it stops working. I've seen this happen rather quickly when passivating pieces sitting in direct sunlight during the warmer time of year.

Ray Kremer
Stellar Solutions, Inc.

McHenry, Illinois

March 28, 2008