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CLINIC PLATING White Spots on Gold pfonline.com/experts plate after the plating process. SEM analysis shows residuals of sodium. Any idea where we produce sodium? The process we use is nickel-gold-tin. —G.S. A. Typically, a white colored gold deposit is caused by excess nickel in your plating bath. Since your SEM analysis indicates sodium residuals and not nickel, we have to assume that the sodium salts are coming from your rinse water or sodium salts used in your plating process. Without additional information on the exact process you are using, I would suggest the following steps to find your source of sodium salts: 1. Check the quality of rinse water used in your rinsing process. 2. Check the quality of water used to make up your process baths. 3. Review the formulation of your process bath chemistries to determine if sodium salts are used in the formulation. If any of these steps indicate the presence of sodium salts, you have your culprit and now must reduce or eliminate it. a bell-shaped fitting with 1/2-inch and 1-inch diameters. We are seeing dark brown stains in the area where the 1-inch diameter is reduced to 1/ -inch. Do you have any 2 idea what the problem is? —M.T. A. First, I suggest you determine if the stains appear when the parts come directly out of the plating bath or if they appear after the final step in the plating process and are allowed to dry off. Without the part in hand or a photo of the part I cannot give you a definitive answer. Quite often staining of the ARTHUR S. KUSHNER type you describe is due to Consultant poor rinsing and drying of platingclinic@pfonline.com the parts after the plating step is complete. Copper Flash on Beryllium/Copper Alloys Failing Electroless Copper Bath Q. Is a copper flash required between a gold plate and Q. I operate an electroless copper bath on a plastics line. beryllium copper (BeCu) base material? I've been told it promotes better adhesion than gold over BeCu base material, but would like to know the technical reasoning behind this. Note, my application does not allow a nickel strike. —W.D. A. As you know, beryllium copper alloys are not the easiest materials to plate. The surface of the base material must be thoroughly cleaned to remove copper oxides and other impurities that are present on the surface. Assuming you clean the surface properly, you can plate directly on the beryllium copper alloy. However, there is another problem that is somewhat more subtle and will cause the plate to not adhere to the surface in a satisfactory manner. This particular problem has to do with copper migrating into the gold layer and forming compounds on the surface between the copper alloy and the gold. These compounds tend to reduce the adhesion of the gold to the base material and discolor the gold layer. This is one reason why a barrier layer such as nickel is plated on the base material. Using a copper layer on the BeCu base material will not solve this problem. As far as using another material as a barrier layer, an alloy plate with the trade name Albaloy is sometimes used to replace the nickel. Albaloy (also called tri-metal alloy or white bronze) is a tin-zinc-copper alloy with properties similar to nickel. We have suddenly started experiencing a "mudding out" condition where the copper is plating onto something in solution and falling out. The bath is not overly active with slow initiation and low plating rates. I used some decorative chrome solution in my etch recovery system about a month ago. The chrome was contaminated with drag out from a microcrack nickel bath. Any thoughts on if this is the issue or am I totally missing something? —P.S. A. My best guess here is that your electroless copper bath is contaminated with material from one of your prior steps. Given the complex chemistry of electroless plating baths, you have probably created an environment in which the copper will plate on one of the contaminants. You might check with your chemical vendor and see if they have a methodology for cleaning up your electroless copper bath. If not, you may have to install a new plating bath and probably the baths used prior to the electroless copper step. Q. I have a problem with whitish-colored spots on my gold Stains Using Cyanide Copper Plating Bath Q. We are using a cyanide-based copper plating bath to plate 58 SEPTEMBER 2013 — pfonline.com Black Spots on Cadmium Plating Q. We have been getting black spots on parts that are cadmium plated. The parts look great when shipped, but they are black when they get returned to us. We have had several labs do test on samples and they all say that it seems to be improper cleaning prior to plating, however this really seems unlikely to me. What are your thoughts are on the issue at hand? The material we are plating is C1018. —S.M. A. I agree with you and do not think the blackening of the