[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:
http://resources.metapress.com/pdf-preview.axd?code=hu72j65756220274&size=largest
<http://resources.metapress.com/pdf-preview.axd?code=hu72j65756220274&size=largest>
Which establishes that the eutectic has an approximate composition of
30:70 Cd:Sn.
For the full article on the Cadmium tin system:
http://www.springerlink.com/content/hu72j65756220274/
Bruce
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