×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Gold embrittlement in Tin solder joints

Gold embrittlement in Tin solder joints

Gold embrittlement in Tin solder joints

(OP)
Since my infancy as a new engineer I have been taught about the gold embrittlement issues related to tin-lead solders, specifically 63/37 alloy.  It has been my understandng that the problem is associated with gold percentages above 3% weight and its intermetallic formation with lead.  To avoid this issue altogether I have often specified the use of Tin-Silver (Sn96) instead of the Tin-Lead when joining gold plated components, without a pre-tinning process.  Recently this approach has come into question and a so called "expert" has said that the issue is the gold forming intermetallics with the tin, not the lead.  Now I know that one of the most popular and historically reliable solders used in microelctronic assembly is gold-tin (Au/Sn 80/20).  My logic tells me that if gold and tin had a problem with each other there would be no way this solder would stand the test of time, so I am crying Bull... on the so called "expert".  Can anyone provide some relavant testimony or insight?

RE: Gold embrittlement in Tin solder joints

If you have questions on the more exotic solder alloys like Sn/Au the tech guys at Indium Corp were (20 years ago - how did that go so fast?) highly knowledgable and fairly free with advice, the more so if it involved one of their products. For the 'common' alloys the equivalent guys at Multicore - which is now part of Henkel, IIRC - were equally knowedgable. Hopefully the acquisition and merger process hasn't diluted the engineering support too much.
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Gold embrittlement in Tin solder joints

(OP)
That white paper is pretty well know and I have seen it before, but it just repeats some of the historical bad news about tin-lead solders.  Ideally what I am looking for is someone that can comment about the tin-silver solders suspectibility to embrittlement, if any.

RE: Gold embrittlement in Tin solder joints

What did the guys at Indium and Multicore say?
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Gold embrittlement in Tin solder joints

(OP)
I sent an email to Indium and got an "oput of office" reply.  I plan to contact Multicore later today if I get a chance.  I have dealt with the Indium folks before and received good support.  Don't know why I didn't think of that one myself.  I appreciate your suggestion.

RE: Gold embrittlement in Tin solder joints

If you get a response please post the gist of it here, it will be interesting to hear from the experts and maybe dispel some of the voodoo hoojoo about gold embrittlement. I'm long out of the hybrids business but still take an interest in stuff which used to be my day-to-day life. smile
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Gold embrittlement in Tin solder joints

There is Kester too..

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources