There is more to this than simply avoiding leaching or formation of
intermetallics on soldering. The alloy choice you make will also be
dependent on the designed/required max processing  and service temperatures.

For example up to 100ish C service you could probably use an In/Pb. Higher
than that you are probably going to have to use alloys which are near brazes
like Au/Sn or In/Au. This is because of solid state diffusion issues and
similar. Some of these alloys may have limited fabrication possibilities or
flux choices. 
Suggest you have a conversation with specialist suppliers so as to make as
informed a decision as possible.

Regards

Mike Fenner
Indium Corporation

T: + 44 1908 580 400
M: + 44 7810 526 317
F: + 44 1908 580 411
E: [log in to unmask]
W: www.indium.com
Pb-free: www.Pb-Free.com



-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of r Tarzwell
Sent: Tuesday, August 23, 2005 9:06 AM
To: [log in to unmask]
Subject: [TN] solid gold boards


hi guys and girls, i have a solid gold board , the tracks are soild plated
gold about 25 microns thick , no ni, over 2 microns of copper   (outer
space reasons) and i was wondering how to solder the components ,   would
the soild gold traces cause brittle joints, or would the large gold ratio
allow a good soilder joint  with lead free solder or any type of solder. I
have no experiance  with soild gold  at all and was hoping some one out
there would has a guess. PS the traces are only 10 microns wide in areas
which is an other problem
robert Tarzwell
director of technology
Sierra Proto express.


***This email, its content and any files transmitted with it are intended solely for the addressee(s) and may be legally privileged and/or confidential. If you are not the intended recipient please delete and contact the sender by return and delete the material from any computer. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. 

Messages sent via this medium may be subject to delays, non-delivery and unauthorized alteration. This email has been prepared using information believed by the author to be reliable and accurate, but Indium Corporation makes no warranty as to accuracy or completeness. In particular, Indium Corporation does not accept responsibility for changes made to this email after it was sent. Any opinions or recommendations expressed herein are solely those of the author. They may be subject to change without notice.***

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------