In a message dated 05/04/99  06:46:26PM,  [log in to unmask]
writes:

SNIP
>  Are you sure gold embrittlement is really a problem?  I don't recall having
>  ever seen any metallurgical reports that say what Au does in Sn96/Ag3.5, so
>  I'm not sure that its limitations are the same as those of Sn63 and
similar.
>  I do recall having worked with the Sn96/Ag3.5 and similar solders years ago
>  and producing some of the ugliest solder joints ever conceived, in a
> cosmetic
>  sense.  The solder joints were quite strong and did the job intended.


Sn96 is more tolerant of Au than Sn63 under the same conditions.
Approximately:
The problem of gold embrittlement is the ratio of Au to Sn, as there is 50%
more Sn in the  SN96, the gold leached into the joint will be 2/3 the level
(with respect to the tin) compared to the same amount (of Au) in a Sn63 joint.

Mike Fenner

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