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Burned rhodium plating solution

I bought a 4 gram concentrate rhodium solution. I mixed it into 2 liter triple AAA distilled water. When I try to plate a jewelry with it the jewelry burns or rather turns into black. need help

Francis Arceo
jewelry manufacturer - Manila, Philippines
2007

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First of two simultaneous responses --

Why don't you ask the people that sold you the stuff? We are human beings Francis, not clairevoyants or magicians. How can we know what exactly did you buy and are doing?

Guillermo Marrufo
Monterrey, NL, Mexico
2007

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Second of two simultaneous responses -- 2007

Francis,
You say you bought Rh concentrate, which probably contained 4 grams Rh metal in the small jar. If you are plating in a 2 liter beaker you have to add some reagent grade sulfuric acid (50 ml/l) There is probably nothing in the bath to give you throwing power. Some baths work well with a little phosphoric acid, it tends to give a whiter deposit. I would start out with 10 ml/l on the phosphoric. Watch your voltage, because you are only at 2 g/l Rh metal, so keep it on the low side.

Mark Baker
Process Engineer - Syracuse, New York