In my column last month I responded to a question regarding electropolishing of platinum. After the column was submitted, I found additional information on the subject. Here is the original question and answer followed by the additional information.
Can you give me a formulation for electropolishing of platinum?
Q. Can you give me a formulation for electropolishing of platinum? V.J.
A. The bottom line answer is I cannot give you an easy-to-use formulation. Most precious metals can be electropolished using a melt containing potassium cyanide, or sodium cyanide and a sulfur-containing compound such as thiourea. This is a dangerous process and not recommended. Another process uses a melt of potassium chloride at 950°C. This is also not a safe process.
Perhaps one of our readers can give me some information on how to perform this process.
Additional Information: I found an excellent recent review on electropolishing of gold and platinum group metals in Metal Finishing magazine. The reference is Terry Jones, “Electropolishing of Precious Metals,” Metal Finishing, 102, #7/8, 2004, pages 45-57. The paper gives multiple formulations and many references. Finding this is an excellent example of why everyone, me included, should “keep up with the literature.”
An overview of precious metal electroplating processes.
Why is it important for you to know this?
Our expert, Art Kushner, says yes, you can color stainless steel, but it is not a process that is typically performed in a plating shop. Read more about his answer.