It should be worse with the eutectic, as it contains less Sn.
Vladimir
SENTEC Testing Laboratory Inc.
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca
-----Original Message-----
From: Gabriela <[log in to unmask]>
Sender: TechNet <[log in to unmask]>
Date: Sat, 16 Jul 2011 17:17:52
To: <[log in to unmask]>
Reply-To: TechNet E-Mail Forum <[log in to unmask]>,
Gabriela <[log in to unmask]>
Subject: Re: [TN] Silver embrittelment in solder joints
Thank you all for the answers.
I think that I formulated my question a little clumsy.
I am also interested if there was a research COMPARING the solder joint
embrittlement for the following two situations:
- Soldering a gold plated lead with Sn/Pb 63/37 solder
- Soldering a gold plated lead with Sn/Pb/Ag solder
Gaby
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
Sent: ו 15 יולי 2011 15:37
To: [log in to unmask]
Subject: Re: [TN] Silver embrittelment in solder joints
Hi Gaby - the issue of silver embrittlement was a topic that Werner and I
had long, torturous, fun, engaging discussions about silver embrittlement
(I miss Werner, he would have some great comments on this topic). Werner
was a participant in a industry consortia in the 1980's where a silver
embrittlement issue happened with some CLCC components. The project data
was semi-restricted so a complete report was never published. The IPC 4-14
committee did some of the most recent work on the topic - look in the IPC
4553 specification, Appendix 6 for a summary of that work. Also IPC-TR-586
contains the entire test report covering the thermal cycle testing the
committee completed. A version of the TR-586 was also published in the
2008 SMTA Toronto Conference proceedings. It takes a greater silver
content in a solder joint to cause embrittlement than gold content. The
4-14 committee showed that you can have up to 30 uinches of immersion
silver surface finish and not have an embrittlement situation under
standard SMT process conditions (and there is no reason to have 30 uinches
of ImAg on a pwb!). The amount of silver in Sn62, even combined with a
typical ImAg surface finish, won't result in a silver embrittlement
situation. Werner had a good point on SAC solder - all sources of silver
need to be accounted for when determining if you could have too much
silver - the silver content of the solder should not be overlooked. Hope
this helps.
Dave Hillman
Rockwell Collins
[log in to unmask]
Gabriela <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
07/15/2011 02:38 AM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
Gabriela <[log in to unmask]>
To
<[log in to unmask]>
cc
Subject
[TN] Silver embrittelment in solder joints
Is there anyone who studied if tin lead solders with 2% silver used for
soldering gold plated leads are less reliable than the classic 63/37
tin/lead solder for the same application because of silver embrittlement
in
addition to gold embrittelment?
The late Werner Engelmaier published an article:
<
http://www.globalsmt.net/smt/index.php?view=article&catid=42%3Acolumns-wern
er-engelmaier&id=13358%3Asolder-joint-embrittlementits-not-just-gold&format=
pdf&option=com_content&Itemid=65>
http://www.globalsmt.net/smt/index.php?view=article&catid=42%3Acolumns-werne
r-engelmaier&id=13358%3Asolder-joint-embrittlementits-not-just-gold&format=p
df&option=com_content&Itemid=65
This article explains silver embrittelment as an addition to gold
embrittelment in lead free solders used for soldering gold plated leads
with SAC.
Is there a correlation between my question and the article?
Gaby
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