Agree, We degold all microwave SMT small outline transistors ("helicopters"), because we had catastrophic gold embrittlement problems. The solder joints were so brittle, that the leads lifted from the pad in the temp cycle tests. We measured as much as 15 micrometers of gold! The semiconductor manufacturer meant, that it is a problem to have control on the gold process on such small parts. What nonsense! Anyway, we are today suspiscious with many gold plated parts and do degolding rather than getting embrittlement. I'll send some pictures to Steve, so you can see what can happen. Horror! Inge -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier Sent: den 2 november 2006 23:06 To: [log in to unmask] Subject: Re: [TN] Gold Embrittlement Hi Amol, I you have imersion Au, Au-embrittlement is not a problem because there is not enough Au. Be careful, however, if your PCBs come from China; I have seen much thicker Au-layers than are possible with iAu. Calculating the wt% of Au in a soldert joint is an exercise in futility, because you have to make the assumption--frequently not warranted--that the SnAu-IMCs are uniformally distributed. In cases where you suspect thicker Au [and for the matter Ag; which is equally as bad as Au in causing SJ-embrittlement] deposits, the safest course of action is to wash the Au (Ag) off by tipping. Werner --------------------------------------------------- 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 -----------------------------------------------------