Werner, Just by your answer to Inge, it proves you are still a sound and practical guy. Probably always will be, provided you don't get overheated on the golf course while the rest of us work to keep our jobs. I had to do a lot of work on this issue while working for Honeywell, and I found out (painfully) that the weight percentage approach alone does not prove/disprove a gold embrittlement issue will or will not occur. It can happen with as little as 1% gold by volume. There are many other factors involved, including the shape of the SJs. And all, once again, remember this is a time-variable phenomena. Nucleation of gold through the SJ takes time. Soldering of gold-plated leads to a circuit board and then performing immediate pull-testing means nothing. This is the reason that paragraph 3.9.3 of J-STD-001D states what it does. And if you need to build Space product (per J-STD-001DS), the rules are even more stringent; you cannot solder any part containing any amount of gold on the solderable portion of the leads, it must be removed. The only exception is if you can prove with "documented objective evidence available for review that there are no gold-related solder embrittlement problems associated with the soldering process being used." Good luck with that. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier /* Sent: Wednesday, July 29, 2009 11:54 AM To: [log in to unmask] Subject: Re: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A SOLDER JOINT Hi Inge, No 'used to be-—I think I still am. If you read my resposes you find that I do not think much of this wt-% approach—and it has nothing to do with the impracticality of it after the fact. Werner -----Original Message----- From: Inge <[log in to unmask]> To: TechNet E-Mail Forum <[log in to unmask]>; [log in to unmask] Sent: Wed, Jul 29, 2009 12:41 pm Subject: Re: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A SOLDER JOINT Werner, You use to be a sound and practical guy. How on earth can you decide the volume %-age of the Au brittle phase content in solder joints. Only way is chemical analysis of some kind, but how do you know then the weight % of respective AuSn phase? /Inge ----- Original Message ----- From: "Werner Engelmaier /*" <[log in to unmask]> To: <[log in to unmask]> Sent: Wednesday, July 29, 2009 3:07 PM Subject: Re: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A SOLDER JOINT Hi Inge, How on earth did you find this gem? Not only does it say all that needs to be said to avoid Au-embrittlement, but it also points out the misgivings about ENIG which certainly have been experienced by many. Too bad, we have not heard from the 'Moon Man' in years—thank god we still get 'tuppence' from Brian. Werner -----Original Message----- From: Inge <mm24727@mu lle.swipnet.se> To: TechNet E-Mail Forum <[log in to unmask]>; [log in to unmask] Sent: Wed, Jul 29, 2009 3:39 am Subject: Re: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A SOLDER JOINT Interesting discussion between Brian Ellis and Earl Moon 11 years ago: /Inge http://dev.smtnet.com/Forums/index.cfm?fuseaction=view_thread&CFApp=1&Thread_ID=2345&#Message9513 ----- Original Message ----- From: "Werner Engelmaier /*" <[log in to unmask]> To: <[log in to unmask]> Sent: Wednesday, July 29, 2009 1:20 AM Subject: Re: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A SOLDER JOINT Hi Thomas, The attached will have to do. Werner Future webinars: September 15, “Fundamentals in Solder Joint Reliability” September 16, “Root Cause Analysis of Solder Joint Failures” September 17, “Solder Joint Reliability for Pb-Free Solders” Future workshops: September 24, IPC Midwest, Schaumburg, IL “Fundamentals in Solder Joint Re liability” -----Original Message----- From: Gervascio, Thomas L <[log in to unmask]> To: [log in to unmask] Sent: Tue, Jul 28, 2009 6:42 pm Subject: Re: [TN] FORMULA FOR=2 0DETERMINING GOLD PERCENTAGE IN A SOLDER JOINT How could I get a copy of it? I thought EP&P was out of print.. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman Sent: Tuesday, July 28, 2009 10:01 AM To: [log in to unmask] Subject: Re: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A SOLDER JOINT Hi Jon - the folks from Lockheed published a very good article on the impact of gold on solder joints including the calculations/material parameters/graphs that would be useful to you. Pull a copy of this article: "Effects of Gold Diffusion on a Near Eutectic Solder Joint", S. Enwright, Electronic Packaging & Production, June 1998, pp 68-72. Good Luck. Dave Hillman Rockwell Collins [log in to unmask] "Roberts, Jon (SA-1)" <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 07/28/2009 07:53 AM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to "Roberts, Jon ( SA-1)" <[log in to unmask]> To [log in to unmask] cc Subject [TN] FORMULA FOR DETERMININ G GOLD PERCENTAGE IN A SOLDER JOINT Does anyone have or know where to find the formula for determining the amount of percentage of gold in a SMT solder joint? Appreciate any help, Jon This communication is intended only for use by the addressee(s) named herein and may contain business confidential and/or legally privileged information. 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