[volt-nuts] Low thermal EMF solder

Bruce Griffiths bruce.griffiths at xtra.co.nz
Thu Dec 17 00:01:10 UTC 2009

Bruce Griffiths wrote:
> Mark Sims wrote:
>> I am in the process of making some low thermal EMF cadmium-tin 
>> solder.   This material has not been manufactured in a very long time 
>> and is pretty much unobtainable these days (despite it being listed 
>> as the product of several companies in India).  It gives the safety 
>> geeks apoplectic fits at the mere mention of the first syllable of 
>> "cadmium"...
>> I have seen references to 60:40 solder and 70:30 Cd:Sn solder.   At 
>> one time I saw a table that showed the characteristics of a few type 
>> of Cd:Sn solders,  but have been unable to locate it.  Does anybody 
>> have any references to the properties of Cd:Sn solders?
> The cadmium tin eutectic has low thermal emf and a 30:70 Cd:Sn 
> composition.
> For some micophtographs of the structure of the solid eutectic:
> http://www.aimehq.org/search/docs/Volume%20071/071-48.pdf
> Bruce
For a plot of the melting point vs composition see:

Which establishes that the eutectic has an approximate composition of 
30:70 Cd:Sn.

For the full article on the Cadmium tin system:


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