We have been brazing terminals to HiVoltage caps long ago. As far as I remember, we used a Copper/Silver alloy, i.e. real brazing, not soft soldering. I set up a induction coil solder machine for that purpose. Now, I don't know where the limit between soft soldering and brazing is, but I mean that PbAg2.5 is soft soldering slightly avove 300C. If you use that alloy at 710C, you certainly have a problem. Must confess that I cannot follow your thinking.. Regards Ingemar Hernefjord Ericsson Microwave Systems -----Original Message----- From: - Bogert [mailto:[log in to unmask]] Sent: den 17 mars 2005 00:21 To: TechNet E-Mail Forum; Ingemar Hernefjord (KC/EMW) Subject: Re: [TN] Capacitor Terminal Silver Braze Problem March 16, 2005 One possible problem may be excessive heat used during the braze process. Do you have any info on what happens to Ag2.5 solder at elevated temperatures. For example, would brazing at 710C cause the noted problem? ----- Original Message ----- From: Ingemar Hernefjord <mailto:[log in to unmask]> (KC/EMW) To: [log in to unmask] Sent: Wednesday, March 16, 2005 6:55 AM Subject: Re: [TN] Capacitor Terminal Silver Braze Problem Great, Steve, your new style will make success. About cap, seems like what I suspected, kind of HiVoltage filter cap. Even with those fine pics, it's not easy to see what is what. From my view, looks like solder fatigue cracking caused by mismatch. Some sources regard that too as 'corrosion', kind of 'mechanical corrosion'. Grain sliding and it's consequencies.... A simple drawing would make tele-analysis easier.. Ingemar Hernefjord Ericsson Microwave Systems -----Original Message----- From: TechNet [mailto:[log in to unmask]] Sent: den 15 mars 2005 20:52 To: [log in to unmask] Subject: Re: [TN] Capacitor Terminal Silver Braze Problem Hi All! It's been one them days...too much to do and not enough hands. Plus, I'm feeling a bit on the lousy side...hope I'm not getting the flu. Anyways, I got Les's pictures up. Go to: http://www.stevezeva.homestead.com and look at "Capacitor Terminal Top View, 4 o'clock Position, 8 o'clock Position, and 10 o'clock Position". I've also changed my website a bit...a little birdie told me it was getting boring... Kind regards, -Steve Gregory- Senior Process Engineer LaBarge Incorporated Tulsa, Oklahoma (918) 459-2285 (918) 459-2350 FAX |---------+----------------------------> | | - Bogert | | | < [log in to unmask]>| | | Sent by: TechNet | | | < [log in to unmask]>| | | | | | | | | 03/15/2005 04:28 | | | AM | | | Please respond to| | | TechNet E-Mail | | | Forum; Please | | | respond to - | | | Bogert | | | | |---------+----------------------------> >--------------------------------------------------------------------------------------------------------------| | | | To: [log in to unmask] | | cc: | | Subject: Re: [TN] Capacitor Terminal Silver Braze Problem | >--------------------------------------------------------------------------------------------------------------| March 15, 2005 Thanks ----- Original Message ----- From: Stephen Gregory< mailto:[log in to unmask]> To: [log in to unmask]<mailto:[log in to unmask]> Sent: Monday, March 14, 2005 9:52 PM Subject: Re: [TN] Capacitor Terminal Silver Braze Problem Les, Send your images directly to me, and I will post them for everyone to view... Kind regards, -Steve Gregory- Senior Process Engineer LaBarge Incorporated Tulsa, Oklahoma (918) 459-2285 (918) 459-2350 FAX - Bogert <[log in to unmask]<mailto:[log in to unmask]>> To: [log in to unmask]<mailto:[log in to unmask]> Sent by: TechNet cc: <[log in to unmask]<mailto:[log in to unmask]>> Subject: [TN] Capacitor Terminal Silver Braze Problem 03/14/2005 06:12 PM Please respond to TechNet E-Mail Forum; Please respond to - Bogert March 14, 2005 Folks, the attached photographs show some type of problem with a silver to ceramic braze joint. The joint provides a seal around a capacitor terminal. The manufacturer rejected the terminal due to the noted conditions. In the photo titled top view, the white area on the outer diameter is a 90% Alumina ceramic. Next to the ceramic is the silver braze connection that connects the ceramic to 304 stainless steel using Ag 2.5 silver solder (i.e., 97.5PbAg2.5). In the middle of the top view photo is a copper terminal. The other three photos show the top view enlarged in the 8 o'clock, 4 o'clock and 10 o'clock positions. As you can tell from the photographs, the silver braze joint appears corroded. Also, there appears to be poor or non-wetting to the 304 SST, or otherwise a crack formed. We used a knife in the area from the one o'clock position to about the 2 o'clock position and were able to easily scrape away the top surface of the braze down to about a 1/64 inch or > depth till we got to solid braze area. We had an analysis performed that did not show any chlorides, just silver and lead. It could be that the stuff we were able to scrape away is some form of lead oxide, not sure. I note that the historical QQ-S-571 specification in section 6 indicates that Ag2.5 solder is subject to corrosion in a humid environment, as is Ag5.5. However, the QQ spec indicates that Ag1.5, which is used interchangeably with Ag2.5, has better shelf life and will not develop a black surface deposit. I don't know if the corrosion for Ag2.5 means just a black deposit, or if the solder joint will fail due to other type of corrosion. I note that J-STD-006 does not include the same information as does section 6 of QQ-S-571. During our qualification testing, we subjected a capacitor to high humidity at high temp for an extended period of time with no evidence of corrosion. Can you folks please answer the following questions? 1. What caused the conditions shown in the photographs? What are the photographs showing? 2. Would brazing (probably a furnace braze, not sure) at too high or too low a temperature cause the condition? 3. Will Ag2.5 corrode in a humid environment? If so, what type of corrosion, and why can it occur? Is it a black surface condition?, or can the corrosion ultimately cause failure of the braze joint? What is the physical science basis for the corrosion? Why does it only occur for certain % of silver content, and not for all % of silver? 4. Why doesn't J-STD-006 have the same info as QQ-S-571 regarding corrosion of Ag2.5 and Ag5.5 solder? 5. Will the corrosion continue? --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask]< mailto:[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]<mailto:[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]<mailto:[log in to unmask]>: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives<http://listserv.ipc.org/archives> Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16< http://www.ipc.org/contentpage.asp?Pageid=4.3.16> for additional information, or contact Keach Sasamori at [log in to unmask]< mailto:[log in to unmask]> or 847-615-7100 ext.2815 ----------------------------------------------------- __________________________________________________________________ This message may contain information that is privileged and confidential to LaBarge, Inc. 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In such event, you should destroy the message and kindly notify the sender by reply e-mail. --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------