[Elecraft] FYI: IC Sockets Tin or Gold plated contacts

[N2EY@aol.com]

In a message dated 5/28/03 8:20:13 PM Eastern Daylight Time, belsley@bc.edu 
writes:


> Gold is a very inactive metal, and, without any real expertise, were I 
> forced to, I would bet that any galvanic activity between tin and gold is 
> essentially zero. I have no doubt that, in principle, Trevor's engineer is 
> correct.  But I suspect the practical content of his remarks are nil.  I'd 
> love, however, to hear from someone who really knows.
> 
> 

This question appears in the Scott Mueller books on "Upgrading And Repairing 
PCs" (my bible on assembling this and several other computers from bits and 
pieces, as well as keeping many others working).

In the Tenth Anniversary Edition, pages 340-344, he discusses gold vs. tin 
for  SIMM/DIMM contacts.

Basically he says that dissimilar metal contact (tin/gold) should be avoided 
because of a type of corrosion called fretting. What happens is that the tin 
oxidizes and deposits itself on the gold. Eventually you get a high resistance 
contact. Tin/tin won't do this, and neither will gold/gold, but tin/gold is 
asking for trouble. 

I'm not a metallurgist, but it sounds reasonable to me. And he cites papers 
available on the AMP connector website. 

The only sockets in my K2 are the ones designed to be there. 

73 de Jim, N2EY


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