Chromium Plating and "Star Dusting"

Q. I work for a company that does not do electroplating but does outsource large amounts of decorative chromium plating. One of our vendors has problems with “star dusting” and tells us that it is the base material and not the plating process itself. Since I am not a plater, I don’t know if I should believe the plater! What do you think? B. J.

 

A. Your question in various forms shows up in my e-mails all the time. There are two issues here: One involves the customer and the other—the plater. The buyer is not that knowledgeable about the electroplating process and the plater wants to continue the traditional “smoke and mirror” approach to electroplating. Surprisingly in most cases as the buyer of electroplating services becomes more knowledgeable, the plating vendor tends to become more honest and realistic about the process.

Now onto the star dusting issue. What is star dusting? It basically is a very fine salt and pepper bright nickel deposit. In many cases, it does not make its presence known until the chromium top layer is deposited. Plating solutions that have tramp metal ions in solutions can cause the star dusting. Such things as iron and zinc metal ions can cause the effect. Also, lack of control of the wetting agent (anti-pitting agent) in the nickel bath can cause this to happen.

No, rarely can you blame the base material! It is a housekeeping/plating bath control issue in most cases.