Inge,

The other products that I forgot to mention were not the hermetic hybrids.
Some commercial products involved use of soldered components and glob-topped
ICs on alumina [or laminate] substrates.

These might also have utilized high tin bearing components, but would have
ended up in a Commercial, Industrial, Instrumentation, or Consumer
application.  The ones I am familiar with did not use high tin.

Steve 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge Hernefjord
Sent: Monday, March 26, 2012 3:20 PM
To: [log in to unmask]
Subject: Re: [TN] NTC RE: [TN] Out of the world tin whiskers

Isn't it remarkable:

JEDEC 142  OBTAINING AND INSPECTING MATERIAL/COMPONENTS FOR HYBRIDS/MCM

Not a word about checking for pure Tin ! With the apparent risk of whiskers,
a line or two about that would not be wrong...or did I miss something? Maybe
I don't have a fresh copy?

Steve, as a specialist on these, what's your comment.

Inge







>   On 20 March 2012 19:50, Stadem, Richard D.
>> <[log in to unmask]>wrote:
>>
>> > Tin whiskers can grow in leaded circuits, ie, CCAs soldered with Sn63.
>>
>> > The issue is that the parts need to be tinned of their lead-free 
>> > original finish, and the ENTIRE LEAD then must be tinned with Sn63. 
>> > If
>>
>> > you leave a portion of a SAC305-finished lead untinned, the line of 
>> > demarcation between the Sn63 solder and the SAC305 C -----Original
>> > Message-----
>> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Joyce Koo
>> >  Sent: Tuesday, March 20, 2012 12:57 PM
>> > To: [log in to unmask]
>> > Subject: Re: [TN] Out of the world tin whiskers
>> >
>> > I thought space is exempt for leadfree.  Why?
>> > --------------------------
>> > Sent using BlackBerry
>> >
>> >
>> > ----- Original Message -----
>> > From: Inge Hernefjord [mailto:[log in to unmask]]
>> > Sent: Tuesday, March 20, 2012 01:47 PM
>> > To: [log in to unmask] <[log in to unmask]>
>> > Subject: Re: [TN] Out of the world tin whiskers
>> >
>> > DO THEY NEVER LEARN!
>> >
>> > Inge
>> >
>> > On 20 March 2012 18:08, Gervascio, Thomas L 
>> > <[log in to unmask]
>> > >wrote:
>> >
>> > > Tin whiskers at Saturn
>> > >
>> > > PASADENA, Calif. -- The Cassini plasma spectrometer instrument
>> > > (CAPS) aboard NASA's Cassini spacecraft at Saturn has resumed
>> operations.
>> > Mission
>> > > managers received confirmation on Friday, March 16, that it was 
>> > > turned
>> > on.
>> > > They plan to monitor the instrument for any unusual behavior.
>> > > Last June, short circuits in the instrument led to unexpected 
>> > > voltage shifts on the spacecraft. As a precaution, mission 
>> > > managers turned off
>> > the
>> > > CAPS instrument while engineers investigated the issue. The 
>> > > investigation led to the conclusion that tin plating on 
>> > > electronics components had
>> > grown
>> > > "whiskers." The whiskers were very small, less than the diameter 
>> > > of a
>> > human
>> > > hair, but they were big enough to contact another conducting 
>> > > surface
>>
>> > > and carry electrical current. Researchers are still trying to 
>> > > understand why whiskers grow on tin and other metals, but they 
>> > > know now that whiskers
>> > can
>> > > grow in space and on Earth. It is believed that these or 
>> > > additional tin whiskers that may grow on Cassini cannot carry 
>> > > enough current to
>>
>> > > cause problems, but will burn out on their own like a lightweight
>> fuse.
>> > >
>> > >
>> > >
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