[volt-nuts] cadmium solder alloy for low thermal emf?

[Andy Bardagjy]

A few months ago I send Indium an email inquiring about low thermal EMF
solders. A good choice is Sn10Pb90, or Indalloy 159.

Andy Bardagjy
bardagjy.com


On Thu, May 30, 2013 at 5:05 AM, Andreas Jahn <Andreas_-_Jahn at t-online.de>wrote:

>
> Hello
>
>
>  I do not imagine cadmium bearing solder being easy to acquire.  The
>> Wikipedia entry for solder says Pb90Sn10 can be used as a replacement
>> for Cd70Sn30 in low thermal EMF applications:
>>
>> http://en.wikipedia.org/wiki/**Solder<http://en.wikipedia.org/wiki/Solder>
>>
>> On Thu, 30 May 2013 04:00:19 +0200, Volker Esper <ailer2 at t-online.de>
>> wrote:
>>
>>
>>> By the way: does anyone know, if Agilent uses special solder alloy? I've
>>> heard that a cadmium containing solder is used to get extremely low
>>> thermoelectric voltages (or voltage differences).
>>>
>>> Is that right? If so, which alloy has to be used?
>>>
>>> Thanks
>>>
>>> Volker
>>>
>>>
> Within LT AN86 Cd60Sn40 is recommended for a limited temperature range of
> 0 to around 40 degrees.
> http://cds.linear.com/docs/en/**application-note/an86f.pdf<http://cds.linear.com/docs/en/application-note/an86f.pdf>
>
> But: the thermal EMF is only zero against copper.
> Most precision integrated (hermetical) cirquits use Kovar. (39uV/K against
> copper)
> Relay contacts will be either copper berillium or another material.
> So in most cases a optimized solder for copper/copper connections will not
> be useful.
>
> On the other side Cd containing solders create very poisonous damps when
> being heated.
>
> With best regards
>
> Andreas
>
>
>
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