My understanding of the addition to silver to Sn/PB solders is that
it will slow the diffusion of the gold into the solder, so that
initially after reflowing there will not be much gold in the solder
(hence a shinier solder joint).  However, with time (and
especially with accelerated temperatures) all of the available gold
will still diffuse into the solder.  So if there was enough gold
present to cause a gold intermetallic problem with pure eutectic
Sn/Pb solder (greater than approximately 4 weight % gold as compared
to the solder), then you will still eventually have an intermetallic
problem with the addition of a little silver to the solder.

Brett Goldstein
EVI, Inc.


> In a message dated 10/26/98 4:22:11 PM Pacific Standard Time,
> [log in to unmask] writes:
>
>>       Also, any comments on whether the addition of silver to
Sn/Pb solders  has any effect on gold embrittlement?
>  Thanks for all responses,
>
>  Larry Morse
>  Celwave Inc.
>  [log in to unmask]
>   >>
>
>

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