Hi! I would agree with the solderability degradation that you were provided. A tin over copper surface finish is going to readily oxidize and also have copper/tin diffusion issues at a temperature of 175C, especially if the time duration is longer that 10-15 minutes. You may be able to restore the solderability of the components by using a very aggressive flux in a solder dipping process. Good Luck. Dave Hillman Rockwell Collins [log in to unmask] - bogert <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 03/02/2008 07:47 AM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to - bogert <[log in to unmask]> To [log in to unmask] cc Subject [TN] Matte Tin Plated Diode Solderability issue March 2, 2008 Folks, we have an OEM that purchased axial leaded diodes from On Semiconductor. Since the diodes were not mil-spec parts, the OEM sent them to a test house for qualification and electrical screening testing. The screening is performed at 175C which I believe is the max storage temp of the part. They also performed solderability testing which failed (<90% wetting). The OEM subsequently solder dipped the parts in Sn63 solder and was able to solder them OK. The part manufacturer indicated the solderability problem was most likely caused by tin migration due to the testing at 175C. Seems to me that since MIL-PRF-19500 includes electrical screening testing, the parts should have been able to withstand the full screening testing with no solderability failures since the parts most likely were made on the same line and samp processing as mil spec parts. Any info you can provide on tin migration or on the manuf position that the solderability failure was the result of the testing at 175C would be appreciated. Have other folks experienced solderability issues for matte tin plated parts? --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 15.0 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 -----------------------------------------------------