I'm often asked by the production guys about risk of Au embrittlement, and they show a board or a component which they suspect having too much of Gold. The first test I use to practise takes 10 seconds to perform. I use a Faber hard rubber pencil and give the board pads or the component terminal a few hard strikes with the pencil. If the underlying nickel comes up immediately, it's a good Au flash, and no risk of soldering. And most of the cases belong to this group. I cannot recommend this 'method' to other than very experienced ones. (If I can go on striking the solder pad without seeing nickel, then I have to do a more advanced examination of course.) Inge ----- Original Message ----- From: "Gervascio, Thomas L" <[log in to unmask]> To: <[log in to unmask]> Sent: Wednesday, July 29, 2009 12:42 AM Subject: Re: [TN] FORMULA FOR DETERMINING 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 DETERMINING 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. If you are not the intended recipient of this e-mail, you > are > hereby notified that any dissemination, distribution, disclosure or > copying of this e-mail and its contents is strictly prohibited. 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