Hi Brian,
How's the surfing.
Agree, and Brian brings up a good point with this characteristic that gold does not go into solution throughout the solder that makes up the solder connection but remains in the periphery areas. This causes localized areas that are suspect to embritlement.
Maybe the accepted limit of 3% which has been commonly applied provided a degree of security for us that there would not be a problem.
 
 

Mel Parrish
Director, Training Materials Resources
Soldering Technology International
102 Tribble Drive
Madison, AL 35758
256 705 5530
256 705 5538 Fax
[log in to unmask]
www.solderingtech.com

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Brian Toleno
Sent: Monday, October 07, 2002 11:40 AM
To: [log in to unmask]
Subject: Re: [TN] Gold Embrittlement


I have done some work looking at gold embrittlement of solder joints and we found a weight percent on the order of 4-5% in eutectic Sn/Pb solder joints can cause embrittlement, in cross sections we saw joints that started with Au-Sn rich globules, turn into needles and collect at the solder joint interface over time leading to embrittlement.  There was a paper from Paul Vianco showing a 4 weight percent of Au in Sn/Pb solder leading to embrittlement.

Brian J. Toleno, Ph.D.
Sr. Applications Chemist
Loctite Electronics
15051 East Don Julian Rd
Industry, CA 91746
Ph: 626-968-6511 x304
Cell: 626-390-9562
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