I wouldn't worry Dave SIR Doug will spend more time trying to get the loco-motive in a sealed k-pak bag to determine the cleanliness between the tracks than bearing down on you. Dewey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman Sent: Thursday, April 16, 2009 12:53 PM To: [log in to unmask] Subject: Re: [TN] NTC - [TN] Gold/Tin Intermetallics, why are we afraid? Hi Joyce! Authority??????? I am just a lowly engineer trying to find the light at the end of the tunnel without having all the alligators in the swamp get me first. My luck will be that the light at the end of the tunnel is Doug driving a train! Dave Joyce Koo <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 04/16/2009 02:48 PM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Joyce Koo <[log in to unmask]> To [log in to unmask] cc Subject Re: [TN] Gold/Tin Intermetallics, why are we afraid? Ha, the authority is spoken! -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman Sent: April 16, 2009 3:32 PM To: [log in to unmask] Subject: Re: [TN] Gold/Tin Intermetallics, why are we afraid? Hi Joyce - my response would "it depends" (and Doug gets another Diet Mt. Dew) as Rockwell Collins utilizes immersion silver pwb surface finishes on many IPC Class 3 type products with no reliability issues. Dave Joyce Koo <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 04/15/2009 04:11 PM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Joyce Koo <[log in to unmask]> To [log in to unmask] cc Subject Re: [TN] Gold/Tin Intermetallics, why are we afraid? "ImAG finishes have a 12-month shelf life in a controlled environment (<35[degrees]C/<85[degrees] RH), which can be significantly shortened when exposed to air pollution with high sulfur and chlorine content. Silver embrittlement Embrittlement A general set of phenomena whereby materials suffer a marked decrease in their ability to deform (loss of ductility) or in their ability to absorb energy during fracture (loss of toughness), with little change in other mechanical properties, such ([Ag.sub.3]Sn intermetallics) of solder joints may occur when the finish thickness exceeds IPC-4553 recommendations and Pb-free, high silver content solders are used. ImAG is not recommended for high-reliability assemblies that must meet IPC-6010 Class 3 requirements, but is acceptable for Classes 1 and 2." http://www.thefreelibrary.com/Will+discoloration+tarnish+ImAg+reliabilit y%3F+Watch+for+silver...-a0193896272 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier /* Sent: Wednesday, April 15, 2009 4:34 PM To: [log in to unmask] Subject: Re: [TN] Gold/Tin Intermetallics, why are we afraid? Hi Vlad, I cannot comment on your specific case, but look at the pics below to see Ag-embrittlement. Sorry 'Netters, IPC strips pics. 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