Hi Jim! I would be very suspect of any Ag/Pd terminations. The Ag/Pd
metallization does not "age" gracefully over time as both temperature and
humidity cause either sulfidation or oxidation issues. Additionally, Ag/Pd
terminations tend to diffuse very quickly into molten solder such that
depending on your solder process time/temperatures, you can be left with a
mechanical solder-to-component body joint which is not the metallurgical
joint you intended to create.  Chapter 3.3.1 of the AWS Soldering Handbook
(ISBN 0-87171-618-6) has some good information. It is my understanding that
the Ag/Pd termination was originally developed for use with conductive
adhesives thus avoiding any diffusion/dissolution issues. Apparently
someone thought soldering to it was a good idea but never checked with a
materials engineer. Unfortunately the Ag/Pd metallizations are making a
"re-appearance" due to the Pbfree activities. Good Luck.

Dave Hillman
Rockwell Collins
[log in to unmask]




                      "West, Jim"
                      <[log in to unmask]        To:       [log in to unmask]
                      M>                       cc:
                      Sent by: TechNet         Subject:  [TN] Silver Palladium Termination
                      <[log in to unmask]>


                      01/14/2004 03:12
                      PM
                      Please respond to
                      "TechNet E-Mail
                      Forum."; Please
                      respond to "West,
                      Jim"






Hi,

Is there a different process required to solder to a silver palladium
termination?  We have ran these through our normal process and noticed that
the parts with they type of termination do not look very good.
Within the same reel, we have noticed some of parts look like they have
some
type of oxide build up because they have a dark gray appearance, while the
others have the silver appearance.  Is this normal for this type of
termination?
Should we treat these different within our process?

Thanks,
Jim

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