Ooooops!!!  That was really informative.
> 
> > 
> >      Has anyone heard of problems with seating a tin/lead leaded part into 
> >      a gold socket?  

Yes, fretting corrosion is a problem with gold-tin/lead contacts.,
especially if mechanical vibrations are present. Fretting corrosion
will cause an increase in contact resistance.  What happaens
is the tin forms an oxide film that mechanically breaks down
with vibration, allowing the newly exposed tin to form
more oxide.  The broken oxide layers that build up degrades
the contact.  The presence of a gold-tin/lead couple exaserbates
the problem.

>>       I have heard concerns that the gold will migrate into 
> >      the tin/lead even though it is only a mechanical connection.
> 

I suppose a little gold may migrate into the tin/lead, but that 
is not the problem in this case.  With gold plate directly over
copper (i.e. without Ni in between) the Cu will migrate into 
the Au plate, and lead to contact degradation.
-- 
Karen Tellefsen
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