I guess there are some absolutes in life - gold embrittlement 
     questions fall into that category! Here are a couple of good papers 
     that maybe helpful:
     
     Manufacturing Concerns When Soldering With Gold Plated Component Leads 
     or Circuit Board Pads, Mark Ferguson, IBM, IPC-TP-1103.
     
     Effect of Gold on the Reliability of Fine Pitch Surface Mount Solder 
     Joints, Circuit World, Vol. 18, 1992, J. Glazer.
     
     The easy way to look at a gold embrittlement situation is two fold:
     
     A) Is there enough solder volume available to allow the gold to 
     dissolve into the solder joint at a level of less than 4% by weight?
     
     B) Does the soldering process have sufficient time and temperature to 
     allow (A) to occur?
     
     This rule of thumb has worked well for me in the past. The answer to 
     (A) is almost always yes, (B) is usually were things are not so rosy. 
     Good luck.
     
     
     Dave Hillman
     Rockwell Collins
     [log in to unmask]
     


______________________________ Reply Separator _________________________________
Subject: ASSY: Gold plated terminations
Author:  [log in to unmask] at ccmgw1
Date:    8/15/96 7:59 AM


     
     This question has come up again.  What are the adverse affects of gold 
plated terminations on SMT components?
     We have been seeing a number of new sample components with gold 
terminations, and to date, have disqualified  them based on gold 
embrittlement. .  Many of the vendors reps say that this issue is new to them 
and that they sell these parts all over with no questions/problems.  Is this 
still an issue?  If so, why are these vendors supplying parts, especially 
taped/reeled parts, with gold on them?  Tinning these would be expensive and 
hardly practical.
     Is there a spec/study/whatever that shows the maximum deposition of 
gold before it becomes a problem?
     
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