Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Excessive precipitation of chrome

I have some problems with the high frequency of replacing the passivation bath (Chrome based) caused by the precipitation of chrome. Can anyone tell me how to prevent this precipitation or how to dissolve or mask the chrome precipitation. Is there a way to filter this precipitation? We keep the pH below 1.4 and the temperature of the bath is 60 °C.

Thanks,

Frans Leest
Steel business - Oosterhout, Brabant, Netherlands
2004

I am very confused by your letter, and the more times I read it the more confused I get because I can't figure out whether you are talking about chrome plating or a chromate conversion process for zinc plating or what, because nothing fits.

Chrome plating baths are almost never dumped, and are never called passivation baths, but they do operate at 60 deg. C.

Chrome passivation baths are dumped regularly, but they are not used on steel, and to my knowledge they are never operated that hot.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

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