22 Feb
2008
22 Feb
'08
7:26 a.m.
I've been told that gold-plated sockets are a
waste of money if what
you're going to be socketing is tinned-lead packages. Something
about gold-to-gold and tin-to-tin makes for the best results.
Well, it reduces corrosion. Whenever you run current through a
junction between metals of differing electronegativities, it promotes
corrosion at the junction. Thus, you want the chip pin surfaces and
the socket surfaces to be the same metal. (Gold is preferred over tin
in a different sense, in the sense that it corrodes less due to
environmental chemical effects. Which effect outweighs the other
depends on things like the local air pollutants, how much time the
metals spend in contact versus exposed to the environment, how much
current is run through the junctions....)
I'd say gold/gold is probably best, since it's the most
corrosion-resistant in both these senses. But whether I'd prefer
gold/tin or tin/tin depends on the tradeoffs.
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