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On 11 Jul 2005 15:32:26 -0700, jim rozen
wrote:

In article , Harold and Susan Vordos says...

I thought 'coin silver' had a lot of nickel in it.


Nope------it's 10% copper, 90% silver, at least here in the US. It was the
standard for striking silver coins, likely the reason it's called *coin
silver*. Canada uses a lower silver content, I think 80%. Other
countries use varying percentages.

There is no nickel in coin silver, never has been, although nickels, during
the war years, were made from silver and manganese, with no nickel content.
It's easy to distinguish the war years nickels (aside from looking at the
dates) because the mint marks are very large. Likely none left in
circulation now, though. They were probably all taken out of circulation
when the silver content exceeded their face value, in the same manner the
rest of our silver coinage experienced.


The term "coin silver" has a specific meaning when used in the electrical
contact industry - and that is quite different than the term when used
in numismatic terms.

I seem to recall that somebody on RCM a long time ago researched this,
and found there was an appreciable amount of Ni in electrical contacts
that were called 'coin silver' and the term had its roots in germany
from long ago.

I suspect the original poster was not refering to silver gotten from
coins for his apparatus. The term seems to be a bit vague, but the
90/10 cu/ag number you cite seems pretty much the standard. If
that meets his needs, it will of course be non-magnetic - but there
may be other more mechanically desirable materials out there.

I still seem to remember somebody here posted historic details
on that alloy that included Ni though.

Jim



Okay, In the interest of the straight poop, I rummaged around and
found my copy of "Butts & Coxe" A lieberal and queer pair of
metalurgists (stolen from another thread) who wrote "Silver Economics,
Metalurgy and Use", VanNostrand, 1967

In their list of "Silver alloys frequently used as electrical
contacts" they list "Coin silver" as 90% Ag, 10% Cu.

While they obviously do not list every alloy ever used for electrical
contacts, the highest nickle content in any of the 15 alloys they have
listed is .5%.

Of course these don't show composite type contacts, where the silver
may be laminated unto a nickle substrate.

Now, to the original poster, while I have this book out, the word
"properties" covers a lot of territory. Exactly which properties are
you interested in.

Paul K. Dickman