Thank you very much to all who answered promptly!...... I think we are okay based on the thickness spec and the acceptable % vol of Au in the joint. Regards, Amol -----Original Message----- From: Leadfree [mailto:[log in to unmask]] On Behalf Of Kane, Joseph E (US SSA) Sent: Thursday, November 02, 2006 1:31 PM To: [log in to unmask] Subject: Re: [LF] Gold Embrittlement You might not need to do a volumetric calculation, because J-STD-001 has done some of the homework for you. You're not required to remove gold from through-hole leads if it's less than 2.5 microns thick (in Rev. D, Para. 3.9.3). If you can't get information from the supplier, XRF can tell you the thickness. -Joe -----Original Message----- From: Leadfree [mailto:[log in to unmask]] On Behalf Of Lester Subrattee Sent: Thursday, November 02, 2006 1:18 PM To: [log in to unmask] Subject: Re: [LF] Gold Embrittlement The typical number going around industry, as far as percentage of acceptable gold in a joint, is about 3 percent. From your data you can approximate how much gold is in the joint and thus determine your safety margin. However, there are two mechanisms at work regarding the "amount" of gold in the joint. If a good nickel/tin intermetallic joint is formed and you have too much gold in the joint (let's say beyond the 3 percent) there could be gold/tin planar intermetallics within the bulk joint which could result in shearing along the intermetallic during impact. So you keep the gold percentage below 3 to be safe. Your work is not done. The other mechanism at work is at the interface where the gold dissolves into the liquid solder. If the soldering process does not allow for sufficient dissolution of gold into the bulk solder you could end up with a gold rich layer in at the interface. This could result in the brittle interfacial fractures. If you address these two, I think you're OK. Hope it helps, LS -----Original Message----- From: Kane, Amol (349) [mailto:[log in to unmask]] Sent: Thursday, November 02, 2006 12:42 PM To: [log in to unmask] Subject: Gold Embrittlement Dear Technetters, One of the connectors that we use in an exempt application just went lead f= ree. The surface finish on the connector is gold over nickel. One end of th= e connector is soldered to the board by tin lead solder, while the other en= d goes into a PTH and is hand soldered, again using tin-lead solder. How ca= n I be sure that gold embrittlement will not be an issue for this joint? Is= there a minimum % of gold that needs to be present in the solder joint for= this to become an issue? If I know the gold plating thickness, pin dimensions, and the PTH dimension= s, can I figure out how much gold % would be in the joint, and hence object= ively conclude one way or the other? What other information do I need? Regards, Amol CONFIDENTIALITY NOTICE:=20 This e-mail, and any attachments, is for the sole use of the intended=20 recipient(s) and may contain information that is confidential and=20 protected from disclosure under the law. Any unauthorized review, use,=20 disclosure, or distribution is prohibited. If you are not the intended=20 recipient, please contact the sender by reply e-mail, and delete/destroy=20 all copies of the original message and attachments.=20 Thank you. ------------------------------------------------------------------------ ---- ---Leadfee Mail List provided as a service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Leadfree To temporarily stop/(start) delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL/(MAIL) Search previous postings at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=3D4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ------------------------------------------------------------------------ ---- --- THIS EMAIL AND ANY ATTACHED FILES ARE CONFIDENTIAL AND MAY BE LEGALLY PRIVILEGED. 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