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Ted Mooney, P.E. RET
Pine Beach, NJ
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PRETREATMENT FOR ELECTROLESS NICKEL ON C11000
2007
I have been plating ENIG on C11000 (electro tough pitch copper) and this includes a persulphate etch. The problem is more of a cosmetic issue than anything else. After the etch we usually see no issues but after the Electroless NIckel we see some heavy spotting or clouding. At this time we have manually scrubbed the parts after gold to get a nice uniform look. My question is if there is a better way. Is it something in the material that is causing the clouding? We have tried two different EN baths with and without etching and both give the same results. PLEASE ADVISE!
Thanks
SS
job shop - ELK Grove, Illinois, USA
Q. I own an electroplating job shop in Bensenville, Illinois. I am having difficulties maintaining a uniform appearance on parts made of C11000. I am trying to plate them immersion gold/electroless nickel. What is the best method of pretreatment for this material prior to Electroless Nickel?
Sincerely,
electroplater - Bensenville, Illinois, USA
2007
A. I'll try and throw my guess at this! The "persulphate" etch you're talking about is most likely ammonium persulphate and I'd guess that the rinsing is inadequate to remove all the alkaline film which is speeding up or inhibiting the initiation reaction. My thought would be to use an intermediate rinse in a 1% solution of straight ammonia ⇦this on eBay or Amazon [affil links] in between the persulphate etch and the EN solution. Another bad practice that you'll run into with a persulphate etch is copper drag-in to the EN solution - using an intermediate ammonia rise will reduce the copper drag-in. Lastly, one thing you didn't mention is how you're initiating the nickel deposition - copper alone in an EN bath won't initiate. What are you doing - nickel strike, touching with iron, palladium catalyst?
Milt Stevenson, Jr.
Syracuse, New York
2007
A. What we do is to etch it will very dilute HCl. The dilution of HCl of C.P. grade up to 5 times for 15 minutes. Although there is Cu-EN etchant available.
Anant Chavan- Bombay, Maharashtra, India
2007
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