In article ,
John R Leddy wrote:

Java Jive;94051 Wrote:
On Sat, 13 Jun 2015 15:35:44 +0100, RJH wrote:
Unlike gold, silver corrodes quite easily. That's why your family
silver needs constant cleaning by the ball of your butler's thumb
wrapped in a suitable cloth.
I'm under the impression silver tarnishes; that's to say, there's a
layer of staining sitting on top of the surface of the silver, which is
easily wiped away with lime juice.
I've been thinking copper corrodes; that's to say, there's a chemical
reaction within the copper itself, which is destructive and similar to
rust in iron.
Anybody have a more precise explanation? Just curious.

As regards switch contacts, silver is certainly a better choice than
copper in terms of staying low resistance. But there may well be a better
'plating' than silver which is also cheaper than gold.

My old car has copper contacts on much of the switch gear. If it is
handling high current, seem to stay working. The same design switches
which are only controlling a relay so low current need frequent cleaning.
They are a design which is is easy to open up, and all the internal copper
parts are often green after a few years. ;-)

--
*The average person falls asleep in seven minutes *

Dave Plowman London SW
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