In article , Dave Plowman (News)
wrote:
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.

IIRC There are a number of different treatings which can generate a 'hard'
(i.e. resistant to being scraped away) don't tarnish, etc. Even 'gold'
tends to be a series of layers of alloys, etc. By itelf, gold tends to wipe
off metal surfaces very easily. I think the coatings involve layers /
alloys using things like rhodium, tec.

Jim

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