In my posting on this topic yesterday, I commented on what I had learned
that an electroless nickel deposit that is too low in phosphorus will be
attacked by the immersion gold bath, resulting, contrary to intuition,
in a high-phosphorus layer, a condition referred to as black pad. If the
phosphorus concentration in the nickel deposit is high enough, it limits
the amount of attack so that this condition does not occur.

When I mentioned this to a colleague, he immediately wanted to know
whether attack by immersion gold would be a concern for electroplated
nickel, which of course does not contain phosphorus. 

This is an interesting question (wish I'd thought of it). Assuming that
electroplated nickel is attacked in an immersion gold bath, is the
extent of attack a concern since there is no prospect of a phosphorus
layer buildup?

 

Gordon Davy 


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