I understand...I'm familiar with Alloy 42/Kovar in leadframe strips I've
plated in a past life.

We plated them up with Cu/Ni/Au without any problems provided the metal
was properly cleaned prior to processing. Our typical cleaning was
electrolytic in nature (a caustic bath using up to 40 amps) then a
sulfuric neutralizer prior to copper flash.

To test our cleaning processes we soldered strips of material
post-clean. The wetting was pretty good which is what we used as a
process indicator for pre-clean.

~tossing out another 2 cents and then some~

Franklin



Werner Engelmaier wrote:
>
> In a message dated 11/02/0 11:36:27, [log in to unmask] writes:
> >Alloy 42 is a Nickel/Iron Alloy developed for among other reasons, it's
> >electrical properties in conjunction tensile/ductility. When cleaned
> >properly Alloy 42 should solder without any problems.
> Hi Franklin,
> Actually, Alloy 42, like Kovar, was developed to have a metal that could be
> used as feed-through for ceramic components with a CTE that would not crack
> the glass frits. Even under the best of circunstances, Alloy 42 wets much
> less readily than Cu, and there is Alloy 42 used in Asia that cames (perhaps)
> from a south Korean mill that is nbot solderable no matter what you do. HP
> ran into this and published a paper on it.
>
> Werner Engelmaier
> Engelmaier Associates, L.C.
> Electronic Packaging, Interconnection and Reliability Consulting
> 7 Jasmine Run
> Ormond Beach, FL  32174  USA
> Phone: 904-437-8747, Fax: 904-437-8737
> E-mail: [log in to unmask], Website: www.engelmaier.com
>
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