Hi Joyce - sorry but the dissolution rate of Pd is a function of the temperature and the solder alloy you are using - straight forward metallurgy and not a quality characteristic. Most of the us are still using the data that Wally Bader published back in the 1960's for successfully setting process parameters for today. What you are describing is a methodology for avoiding having Pd embrittlement issues. I agree with you that keeping the Pd plating layer thin makes the soldering process easier but if I know the Pd thickness then I can set my soldering process time/temperatures accordingly to avoid having solder joint integrity issues. Dave From: Joyce Koo <[log in to unmask]> To: "[log in to unmask]" <[log in to unmask]>, "[log in to unmask]" <[log in to unmask]> Date: 03/12/2013 05:40 PM Subject: Re: [TN] IPC-7095C vs IPC-4556 ENEPIG for SnPb Dave, I disagree with the dissolution rate of Pd. It depends: the plating quality make all the difference. The eutectic Pb-Sn solder is capable to dissolve Pd rather rapidly and form plate like intermetallics that could change fracture dynamic of the joints. Keep it thin (less than 1000 A) or protected Pd with other metal layers in order to limited time to exposure to the solder could be beneficial. No publication on my side, just 1st hand experience way back in the dark age. -------------------------- Sent using BlackBerry ----- Original Message ----- From: David D. Hillman [mailto:[log in to unmask]] Sent: Tuesday, March 12, 2013 06:24 PM To: [log in to unmask] <[log in to unmask]> Subject: Re: [TN] IPC-7095C vs IPC-4556 ENEPIG for SnPb Hi Kevin - I disagree with that statement in the IPC-7095C and didn't realize it was there (otherwise I would have turned in a comment during the draft efforts). I'll make sure to bring the topic back up in the 7095 committee as we start our next set of standards revision activities. Rockwell Collins has successfully used ENEPIG surface finishes in tin/lead and lead-free soldering applications for several years. We are in the process of running another test sequence with one of the DOE legs using ENEPIG surface finish so I should have an additional data set I can present to the 7095 committee for review in regards to the wording you detailed. Pd has very slow diffusion/dissolution characteristics in a soldering process so you need to make sure you accommodate those metallurgical reactions. But - overall- the IPC-7095C represents a huge amount of work by the committee with tons of new information that should be very useful to the industry. Dave Hillman Rockwell Collins [log in to unmask] From: "Glidden, Kevin" <[log in to unmask]> To: <[log in to unmask]> Date: 03/12/2013 04:35 PM Subject: [TN] IPC-7095C vs IPC-4556 ENEPIG for SnPb Sent by: TechNet <[log in to unmask]> Finally taking a few minutes to glance through some of the new IPC releases... I see a statement within IPC-7095C, specifically section 5.3.3.3, that states ENEPIG is best suited for Pb-Free soldering, and that studies have shown ENEPIG does not produce very reliable tin/lead solder joints, due to the inability of Pd to alloy with lead. I don't see any such warnings or statements in IPC -4556. Or am I missing them? If this is true, it seems like it would be a major consideration and would/should be included or mentioned in IPC-4556 Section 1.4.7 "Limitations of ENEPIG". But, I could have it all wrong. So far all I have done is glance through these new specs.... Kevin Glidden ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. 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