While reading some papers on SnBi solder and SAC solder interaction, I stumbled onto this set of statements in a 2010 paper Copyright ACI, The Lead Free Electronics Manhattan Project - Phase II. Intermetallic Fracture . With Cu supplied by the solder, attaching to Ni pads can be problematic . (Cu1-xNix)6Sn5 intermetallic IMC forms over a layer of Ni3Sn4 at the Ni pad . The Ni atoms are substituted on the Cu lattice . Weak boundary between intermetallics . Mechanical shock and handling risk The statements were associated with a image "SnNi and SnNiCu intermetallic compounds found when using SnAgCu solders," IPC/Soldertech Global 2nd International Conference on Lead Free Electronics. We don't do much Pb-free soldering. But all of our boards, or nearly all, are gold over nickel. Is this a real concern? Wouldn't this kill ENIG as a SAC compatible finish? ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________