Forgot who asked for possible intermetallics, OK, am not an expert myself but found these for ordinary solder situations with Au,Ni,Pd,Sn,Pd and In involved in solder joints (from Wassink) :

AuSn, AuSn2, AuSn4, Ag3Sn, Cu4Sn, Cu3Sn8, Cu3Sn, Cu6Sn5, Pd3Sn, Pd2Sn, Pd3Sn2, PdSn, PdSn2, PdSn4, Ni3Sn, Ni3Sn2, Ni3Sn4, Pt3Sn, PtSn, Pt2Sn, PtSn2, PtSn4, AuIn, AuIn2, Ag3In, AgIn2, Cu3In, Cu9In4, Pd3In, Pd2In, PdIn, Pd2In3, Ni3In, NIIn, Ni2In3, Ni3In7, Pt2In3, PtIn2, Pt3In7...pant..pant..

All these are thermodynamically stable and normal. So, If I understand right, you need not know all about the above intermetallics, just see that they look normal. And only a few seem to be a disaster. Purple plague is of course not wanted, but many of the intermetallics are the result of quite a normal soldering process. Sorry for misleading by speaking about Sn3Ni4, should be Ni3Sn4, you easily stumble in that jungle above.

Ingemar Hernefjord
Ericsson Microwave Systems

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