plating, anodizing, & finishing Q&As since 1989
We are experiencing adhesion problems between sulfamate nickel and acid copper. The adhesion loss is mostly in the low current density areas. I wonder if anyone has suggestionsDonald G. Brown
- Paducah, KY, McCracken
Try entering the acid copper with the current on. Make contact to the rack before entering the tank. The voltage should be higher than normal plating voltage (CD) to cover the low CD areas quickly. If it takes any small amount of time to start electroplating an immersion (chemical replacement) deposit takes place that always has poor adhesion. Another method is to use a cyanide copper strike prior the acid copper (with good rinsing and a mild sulfuric acid dip) There are also non-cyanide alkaline copper strikes that could work as a pre copper to prevent immersion deposits.
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [affil link to the book on: Amazon or AbeBooks ])
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