David Spencer wrote:
> Background
> I have been working on, or should I say "I have been worked over by..", the
> requirements of GR-78-CORE. Requirement R6-8 states, "Silver shall not be
used
> as a conductor or contact finish. [] Tin shall not be used as a conductor or
> contact finish unless subjected to an approved reflow process."
>
> During our prototype phase, we have used immersion gold. Our Mfg. Eng.
wants to
> move to immersion silver or white tin, because the gold is expensive and
can have
> solderability/reliability problems related to the nickel plating under the
gold flash.
>
> Questions
> Does anyone have a ruling on the use of silver or white tin immersion
finishes from
> any of the RBOC's as it relates to the requirements of GR-78-CORE?
>
> Are there any documented tests of these finishes available, i.e.
accelerated aging,
> solderability, insulation resistance, etc ?
>
> Does anyone have experience with either of these finishes in the
hygroscopic
> dust/gaseous contamination test suite from GR-63-CORE?
>
> Thanks for your help!
> Dave Spencer

Hi Dave,
Be careful with Ag; I am sure you heard about 'gold embrittlement' of
solder--silver is worse.
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

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################