Hello Peter, Soldering PdAg or PtAg metallisations is not compatible with leadfree solder. The silver from the metallisation leaches out from the metallisation structure during the soldering operation and forms little holes (voids) at the interface. The remaining intermetallic structure is solid and brittle at the interface solder/Pd. In time the phenomenon increases by solid state diffusion of the silver from the metallisation into the bulk of solder and forms Kirkendahl voids, see picture 446. But the solution is there: Also capacitors with NiSn metallisation is available, see picture 457. Peer Langeveld Consultant Soft Soldering Processes The Netherlands 2007/1/31, Peter Barton <[log in to unmask]>: > We are seeing unusual soldered joints when soldering to components with > Platinum/Silver metallised terminations. At the margin between the bottom of > the component termination and the PCB surface there are a number of > blowholes in the bulk solder. There also appears to be poor wetting to the > vertical end of the termination itself. All other solder joints on the > assembly in question are good, well wetted and on a number of other plating > finishes. > > The solder paste is SAC305 and the PCB finish is ENIG. Reflow is carried out > in a vapour phase process with a maximum assembly temperature of 235 deg. C. > Time above liquidus (217 Deg C.) is around 50 seconds. > > I have requested feedback from the component manufacturer but it's like > pulling teeth so in the meantime I an seeking your considered opinions. > > Many thanks > > > > > ----------------------------------------------------------------------- > Peter Barton > Senior Process Engineer > ACW Technology Ltd > Dinas Isaf West > Tonypandy > Mid Glamorgan. CF40 1XX Wales > > Tel: 01443 425275 (direct) > Fax: 023 8048 4882 > International Tel : +44 1443 425200 > International Fax : +44 23 8048 4882 > Website/URL: www.acw.co.uk > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 > ----------------------------------------------------- > --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------