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Soldering to Kovar like materials

I would like to solder to Carpenter Technology Glass Sealing #42 alloy (similar to Kovar). I would like a solderable surface, preferably Gold or Tin, although pure Tin maybe problematic due to Tin whiskers. Is there a certain stack-up required or does my finisher know what to do, and I just need to specify the top most material?

Thanks,
Bob

Bob Benward
engineer - Smithtown, New York
July 15, 2010

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2nd important question is of course if your soldering process matches with the predictive nature of these aging conditions, something you have to prove yourself.

Best regards,

Harry.

Harry van der Zanden
consultant - Tilburg, Netherlands
July 23, 2010

Dear Bob,

Yes a good plater should know how to handle this.
The question however is if you would base the relation on trust only. I guess not, so you should specify after which aging conditions you still expect your material to be solderable. If for example you specify after 300 hr at 500÷C, I still expect it to be solderable without any fluxing....then it will be very difficult to find a plater who wants to guarantee that, but standard aging tests like 16 hr 155÷ C air or 24 hr. 85/85 RH/T and after this dip and look, 95% coverage should be no problem.