Metal finishing Q&As since 1989

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Chromic Acid

 

I am wondering if Chromic Acid can be used for chromating steel. Can the chromium be isolated and used, or are other methods preferable. I have several bottles of highly concentrated Chromic Acid that I plan to dispose of as hazardous waste if I deem them unusable. Thank you for your help.

Eric C
[last name deleted for privacy by Editor]

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Hi Eric,

It is quite common to use chromic acid as an ingredient in commercial chromating formulations. Chromic acid by itself will not produce a very good conversion coating.

George Gorecki

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Earlier I asked if Chromic acid could be used for plating. What other chemicals are required for zinc chromating? What is the procedure for the zinc chromating process? Can I expect excellent results with a bit of practice? Thanks for your help.

Eric Cieszkiewicz
2005

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Eric, we sympathize with your having some drums of chromic acid on your hands, but you will compound your problem rather than ameliorate it if you try to use these chemicals to chrome plate something or zinc plate & chromate something. Chrome plating and zinc plating & chromating are complicated operations of many steps; you would need to buy alkaline cleaners, acid activation baths, and sulfuric acid before you could gainfully use the chromic acid for plating. And to zinc plate and chromate is even more complicated, assuming someone would give you the trade secrets of how to make viable chromating solutions.

If these are fresh, unopened containers of chromic acid you may be able to find a lab or plating shop to take them off your hands. If you try to use them they become waste and you have between 90 and 180 days to dispose of them as hazardous waste. Good luck.

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