MIGRATIONS
What do you recommend as a minimum thickness for the copper intermediate layer?
Q. We plate components made from brass with copper followed by bright acid tin. Our concern is the potential migration of zinc from the brass substrate into the tin layer. What do you recommend as a minimum thickness for the copper intermediate layer? K.M.
A. If you ask people in the industry you will get recommendations that vary from 0.001–0.004 inch. I usually recommend 0.003 inch.
Why I recommend a greater thickness: Over time zinc will migrate through the copper barrier layer depending on time and temperature. A thicker layer will require a longer time for this to happen.?
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