Ryan/Guenter 
 
This is going to be interesting (thanks for the note Ryan) ;
 
I just thought, on this particular Bismuth alloy, why is it considered right
from start ? :
It's got more lead than standard 63/37 SnPb !
When we say Leadfree ; do we mean 0 lead ? 
I can't see much point in exercising options with more lead still ; however
interesting the subject may be .
 
Am I missing something ?
 
Talking about learning as much as ; does anybody have access to Hitachi ;
IBM ; etc. internal reports on leadfree evaluations in some nonproprietary
form ?
Yes ; I know it's wishful cry 
 
 
Paul Klasek
http://www.resmed.com <http://www.resmed.com> 
 
 
 
-----Original Message-----
From: Ryan Jennens [mailto:[log in to unmask]] 
Sent: Thursday, June 24, 1999 11:19 PM
To: [log in to unmask]
Subject: Re: [LF] Recommended ALLOYS ; independent papers


Guenter-
 
    I have had some dialogue with Dave F. about the suitability of
43Sn43Pb14Bi solder paste.  I have attached his e-mail and he says that
during reflow a new alloy forms which has a melting point of 98C.  This new
alloy has lower tin and lead contents and a raised Bismuth content.  Where
does the extra Bismuth come from and where does the tin/lead go?  I am going
to guess in advance that an exclusively tin/lead alloy forms along with the
Bismuth alloy with a different crystal structure.  Why doesn't this alloy
form when the original alloy is formed for the paste manufacturer?  Thanks
in advance.
 
Trying to learn as much as I can,
Ryan Jennens
TelGen Corporation 

-----Original Message-----
From: Leadfree [mailto:[log in to unmask]]On Behalf Of Guenter Grossmann
Sent: Thursday, June 24, 1999 4:43 AM
To: [log in to unmask]
Subject: Re: [LF] Recommended ALLOYS ; independent papers


Paul

I find it hard to find good papers regarding lead-free soldering. In my
opinion there are not many alloy in sight that can substitute Tin / Lead. 
- Indium alloys not suitable, not enough Indium
- Bi alloys dangerous since not usable with lead containing alloys
(components). Lead will alloy with Bi lowering the melting point below 100°C
- Tin- Copper: has the highest melting point of all lead free solders
- Tin Zink : I have not much infos.
- I think ternary alloys such as SnAgCu will be the best choice.

Reliability is not yet satisfactorily tested ( I think ). I will try to
start a project ( sigh ) next year.

Best regards

Guenter
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