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  for Metal Finishing since 1989
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Safely cleaning chromium plated copper

Hi, I need to clean a chromium plated copper plate. I use the plate for rheology experiments and I keep getting traces of previous samples on my experiments. I know I can get rid of the contamination using concentrated inorganic acids like sulfuric acid, nitric acid, or hydrochloric acid but I am afraid that it could corrode the chromium plating on the copper plate. Concentrated sodium hydroxide could also solve the problem. Do you know if it will be safe to use any of these acids or the sodium hydroxide on the chromium plating?

Esteban Urena-Benavides
Graduate Student - Clemson, SC, USA
January 16, 2009

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First of two simultaneous responses --

Chrome is quite resistant to nitric acid, somewhat resistant to sulfuric and caustic but not resistant to hydrochloric acid. On the other hand, copper is somewhat resistant to hydrochloric but not to sulfuric, nitric and caustics. The problem of using nitric is that, eventually, the acid may reach through the chrome and ruin the part.

Guillermo Marrufo
Monterrey, NL, Mexico
January 22, 2009

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Second of two simultaneous responses --

Try next formula:47,5 gr sodium gluconate/47,5 gr citric acid ⇦this on eBay or Amazon [affil links] / 5 gr tartaric acid ⇦this on eBay or Amazon [affil links] /1 lit water(according to one expired US patent).Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia
January 22, 2009