Dear Lady,
Not me saying tin whiskers grow even on alloys. As whiskers are singlecrystal issues, you are right about pure Tin. Guess pure Tin can appear locally in an alloy, not so remarkable. Now, my very q was matte tin vs cercaps mounting with solder and metal filled epoxy. If you look in preferred list of glues, some claim they have glues that suit for soldered end caps as well as silver plated. Then I came to think of matte tin. If you go back in time, people used to be afraid of using glues on tinned terminals. But that warning was generalizing, because there are many 'tinning' processes and they may behave different vs. glues, which do behave variably too. So, you have an x (end cap finish) and a y (the glue) and a z (the mounting process).
Again, if matte tin is 'reborn' (article by Sandra), what is the propietary metal filled glue for mounting on that finish? Hmm..guess I'm talking to the stars..who can answer such a question without involving too much business and company tactics..
Thanks for your attention, jk
Ingemar
PS. I suspect you read our mails in secret, Paul Klasek, come out of your den immediately, and step up on the arena and fight, dr Oz!
-----Original Message-----
From: Joyce Koo [mailto:[log in to unmask]]
Sent: den 19 juni 2002 13:55
To: TechNet E-Mail Forum.; Ingemar Hernefjord (EMW)
Subject: RE: [TN] tin whiskers - matte tin
Are you sure that "tin whiskers can grow on ALL tin alloys"? I thought only
pure under pressure (internal or external) are the ones got into trouble
(may be it is new century, it becomes more sensitive). 97% usually OK in
the past (if no pressure, no residue ionics).
As long as you use them fast, both solder and glue should be fine (solder =
real one with Pb in it; glue = well formulated and no flake separation from
its organic matrix). no body like stress, including parts finishing...
jk
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]]On Behalf Of Ingemar Hernefjord
>(EMW)
>Sent: Wednesday, June 19, 2002 5:11 AM
>To: [log in to unmask]
>Subject: [TN] tin whiskers - matte tin
>
>
>Hi,
>had a chat with NASA about a little tin whisker problem we had.
>Pure tin end caps on ceramic capacitors. Now, Sandra Winkler wrote
>that tin whiskers can grow on ALL tin alloys, not only pure tin,
>as some thought. Remedy is matte tin and tough disciplin in the
>plating organisation. I'll check with AVX and the others what
>solder they will use from now on. Happened to read this last year:
>
>"At the one-day joint MEPTEC (MicroElectronics Packaging & Test
>Engineering Council)/San Jose University Lead Free Summit on
>January 10, 2001, matte tin was universally supported by the
>attendees by the end of the session. Over 50 companies and nearly
>100 individuals were represented. Remarkably, matte tin has made a
>comeback and will hopefully be here to stay." Sandra Winkler
>
>Q: do you ask for matte tin on cercaps for both solder- and epoxy mounting?
>
>/Regards/
>Ingemar Hernefjord
>Ericsson Microwave Systems
>
>-------------------------------------------------------------------
>--------------
>Technet Mail List provided as a free 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 Technet
>To temporarily halt delivery of Technet send e-mail to
>[log in to unmask]: SET Technet NOMAIL
>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/html/forum.htm for additional
>information, or contact Keach Sasamori at [log in to unmask] or
>847-509-9700 ext.5315
>-------------------------------------------------------------------
>--------------
>
---------------------------------------------------------------------------------
Technet Mail List provided as a free 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 Technet
To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL
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/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
