[Orcnet] Interesting articles on risks of removing lead from solders

[Keith Lofstrom]

http://www.edn.com/index.asp?layout=article&articleid=CA6477864

The bottom line is that current lead-free solders grow whiskers
that short out closely spaced pins (1mm or less).  The article
doesn't say why, but this is typically due to strain relief in
the crystalline tin;  eutectic PbSn solder is amorphous, while
pure metals form rigid little crystals that don't deform easily,
so there is a lot of strain energy to be relieved by spewing
out long skinny crystals.  

Keith


-- 
Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs