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Gold plated stainless foil for solderability
Q. We are trying to plate .0005 inch thick 302-303 SS foil with gold so that it can be soldered to a printed circuit board (PCB). The problem we are having is that the foil is not consistently adhering to the PCB. After we clean the foil with Ritaline and Acetone [affil. link to info/product on Amazon] we put down a "flash" of nickel and then a "flash" of gold. We have been advised that this results on poor "solderability" and what we need to do is plate a thick layer of copper (50 to 100 micro inches) between the nickel and the gold. Your comments?Ashok Sabata
medical device - Sea Bright, New Jersey
Ed. note: Are you sure of the spelling on "Ritaline", Ashok? We find that to only be the French spelling of the ADHD drug "Ritalin".
A. I do not understand why you would like to do that. It is not advisable to plate copper next to gold as both will interdiffuse and make gold lose properties.Guillermo Marrufo
Monterrey, NL, Mexico
A. Gold over nickel has great solderability, A flash of Nickel and a flash of Gold does not. I would recommend a minimum of 5 microns Ni, and spec a woods nickel for the stainless for best adhesion. followed by 2.5 microns Au. If you plate a flash of Au on copper and submit it to normal PCB soldering, the Gold will be absorbed in the copper as an intermetallic, so if you choose to use copper put down a min of 2.5 microns Au.
Hope this is helpful.Jim Campbell
Metal Reclamation - Belleville, Ontario