Eric, Have you not seen this good source: the corrosion doctors? Lots to read about metal corrosion: http://www.google.com/custom?q=lead+corrosion+rates&hl=sv&lr=&ie=UTF-8&oe=UTF-8&cof=AWFID:f726934c33ffd3b9%3BL:http://www.corrosion-doctors.org/CorrDocs/images/logoL.gif%3BT:Corrosion_Doctors_Web_site%3BAH:center%3BS:http://corrosion-doctors.org%3B&domains=corrosion-doctors.org&sitesearch=corrosion-doctors.org&start=20&sa=N On your q: don't know if Pf-free is better or worse than Sn/Pb, assume we've not done so many tests yet to give a satifactory answer. As Tin is a superb coating for marine equipments, I think the high Sn %age in leadfree solders ought to be a positive factor. We have kilograms of reports telling about diff between the two categories, but they all have something in common: very little about corrosion. Ingemar This communication is confidential and intended solely for the addressee(s). Any unauthorized review, use, disclosure or distribution is prohibited. If you believe this message has been sent to you in error, please notify the sender by replying to this transmission and delete the message without disclosing it. Thank you. E-mail including attachments is susceptible to data corruption, interruption, unauthorized amendment, tampering and viruses, and we only send and receive e-mails on the basis that we are not liable for any such corruption, interception, amendment, tampering or viruses or any consequences thereof. -----Original Message----- From: Eric CHRISTISON [mailto:[log in to unmask]] Sent: den 5 maj 2004 11:00 To: 'TechNet E-Mail Forum.'; Ingemar Hernefjord (KC/EMW) Subject: RE: [TN] Corrosion resistance of Ni/Au plating Ingemar/David, Certainly one customer uses salt spray because the alternative corrosion tests require much more specialised equipment. I presume that their specification is based on the experience of having several hundred million phones in use in the field and a pass gives them a degree of confidence that nothing horrible will go wrong in the field. After all corrosion failures are some of the most expensive types of failures you can have. You're unlikely see anything happen for several months by which time a phone manufacturer will have shipped several million units to their customers... Thanks for the guidance - certainly gives pause for thought. One other thing - no one has answered my last question which I asked out of curiosity. Are lead free solders generally more or less corrosion resistant that Sn/Pb? Regards, Eric Christison Msc Mechanical Engineer Consumer & Micro Group - Imaging Division STMicroelectronics 33 Pinkhill Edinburgh EH12 7BF UK Tel: +44 (0) 131 336 6165 Fax: +44 (0) 131 336 6001 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Ingemar Hernefjord (KC/EMW) Sent: Wednesday, May 05, 2004 8:03 AM To: [log in to unmask] Subject: Re: [TN] Corrosion resistance of Ni/Au plating From our point of view (mobile making too) salt spray test seems a very harsh test to perform on such a board. You have gold, copper, tin, lead, nickel, iron and lot more in that soup. Add temperature and chlorine and you'll have a fermentation bucket, like making own wine. Only way to get an inert board in your case would be to wax the whole thing. I'm little curious (Sony-E reading this?), why salt spray on a commercial pocket thing? We have salt spray chambers, but they are most oftenly used for comparison of e.g. chromated parts from various suppliers. Ingemar This communication is confidential and intended solely for the addressee(s). Any unauthorized review, use, disclosure or distribution is prohibited. If you believe this message has been sent to you in error, please notify the sender by replying to this transmission and delete the message without disclosing it. Thank you. E-mail including attachments is susceptible to data corruption, interruption, unauthorized amendment, tampering and viruses, and we only send and receive e-mails on the basis that we are not liable for any such corruption, interception, amendment, tampering or viruses or any consequences thereof. -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Eric CHRISTISON Sent: den 4 maj 2004 18:45 To: [log in to unmask] Subject: Re: [TN] Corrosion resistance of Ni/Au plating It's a mobile phone application. Salt mist is often used as a way of obtaining a measure of the general corrosion resistance of an assembly. However I'm sure you could spend your coffee break thinking up salty environments anywhere in the world that a mobile phone could experience.... Eric Christison Msc Mechanical Engineer Consumer & Micro Group - Imaging Division STMicroelectronics 33 Pinkhill Edinburgh EH12 7BF UK Tel: +44 (0) 131 336 6165 Fax: +44 (0) 131 336 6001 -----Original Message----- From: David Douthit [mailto:[log in to unmask]] Sent: Tuesday, May 04, 2004 5:56 PM To: TechNet E-Mail Forum.; Eric CHRISTISON Subject: Re: [TN] Corrosion resistance of Ni/Au plating Eric, Just exactly how does this "salt fog" test correspond to your possible end use environments? David A. Douthit Manager LoCan LLC Eric CHRISTISON wrote: >Ok, thanks for the info. > >No clear cut answers but I guess PCB finish doesn't make that much >difference. > >Can anyone tell me if lead free solders perform better in corrosive >environments? > >Thanks, > >Eric Christison Msc >Mechanical Engineer >Consumer & Micro Group - Imaging Division >STMicroelectronics >33 Pinkhill >Edinburgh >EH12 7BF >UK > >Tel: +44 (0) 131 336 6165 >Fax: +44 (0) 131 336 6001 > > >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman >Sent: Tuesday, May 04, 2004 3:48 PM >To: [log in to unmask] >Subject: Re: [TN] Corrosion resistance of Ni/Au plating > > >Hi folks! Some additional data - we (e.g. the industry technoweinees) >are much too quick to jump to the conclusion that we have a galvanic >compatibility problem when using either immersion gold or immersion >silver pwb finishes. Rockwell Collins published a paper at the 2003 IPC >Fall meeting which demonstrated that the galvanic impact was secondary >to a standard corrosion reaction in a salt fog test - i.e. our tin/lead >test samples which were in a galvanically happy couple situation >underwent healthy corrosion. The galvanic compatibility tables are very >important and should not be ignored but they also can be misleading >depending on the environment/configuration. Collins has a follow up >immersion silver, immersion gold, immersion tin, and tin/lead galvanic >corrosion study in progress and will report the results sometime in >early 2005. > >Dave > > > > Vladimir Igoshev > <[log in to unmask] To: [log in to unmask] > > cc: > Sent by: TechNet Subject: Re: [TN] Corrosion >resistance of Ni/Au plating > <[log in to unmask]> > > > 05/04/2004 09:19 > AM > Please respond to > "TechNet E-Mail > Forum."; Please > respond to > Vladimir Igoshev > > > > > > > >Rudy, > >It's not supposed to be any Au layer left after re-flow. It desolves in >solder. > >Vladimir >Sent from my Blackberry Wireless >Vladimir Igoshev, 519-888-7465 ext.5283 > > >-----Original Message----- >From: Rudy Sedlak <[log in to unmask]> >To: [log in to unmask] <[log in to unmask]> >Sent: Tue May 04 10:05:27 2004 >Subject: Re: [TN] Corrosion resistance of Ni/Au plating > >Central to this issue is the question of whether the Gold was >completely covered by the Tin/Lead solder. > >I suspect it was not, and if it was not, this would set up a galvanic >cell, which would accelerate the attack on the Tin Lead dramatically. > >Rudy Sedlak >RD Chemical Company > >--------------------------------------------------- > >--------------------------------------------------- >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 >847-509-9700 ext.5315 >----------------------------------------------------- > >--------------------------------------------------- >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 847-509-9700 ext.5315 >----------------------------------------------------- > > > > --------------------------------------------------- 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------