Re: [Phys-L] composition of US coins

[bernard cleyet <bernard@cleyet.org>]

Right, it’s called coin(age) silver — I think the hardening method is precipitation definitely, IIRC, Cu in Al.  It involves dissolution and then aging.  Or it might be simple solution hardening.  (See C in Fe)


http://userblogs.ganoksin.com/binnion/2013/01/02/age-hardening-sterling/  


Hardening of C in Fe is quite different, as it involves the “size” difference between Fe and C.  


bc,     taught engineering materials (Hartnell Community College) and has forgotten v. much.  (ca. ca 2000)


BTW,  You (William W.)  managed to keep the Pu source.  Santa Cruz gave theirs to the NRC, malheureusement!  



We used 1/4 $s  and Ag “brazing” rod. (purer, I think.)  

BTW sterling silver is not “sterling", it’d be v. much too plastic and soft.   


> On 2016/Dec/01, at 11:16, Todd Pedlar <pedlto01@luther.edu> wrote:
>
> I believe the other 10% is copper
>
> On Thu, Dec 1, 2016 at 1:14 PM, William Wehrbein <wmw@nebrwesleyan.edu>
> wrote:
>
> > We use some "old" dimes and quarters for neutron activation experiment. I
> > understand that they are 90% silver. What is the remaining 10%?
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>
>
> -- 
> Todd K. Pedlar
> Associate Professor of Physics
> Luther College, Decorah, IA
> pedlto01@luther.edu
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