Jim,
Since late December 2004 I've been doing an extensive study on designing
lead-free, RoHS-compliant, and WEEE-compliant electronics. To date I
have collected over 125 books and well over 5,400 papers/reports/
magazine articles/web pages on these subjects. I have links to over
2,350 of these documents that are available for free via the Internet,
in my now-344-page Bibliography at
http://www.dbicorporation.com/rohsbib.htm
I've run across quite a few studies on the failure modes, reliability,
and longevity of lead-free electronics. Personally, I think that we are
going to be darned lucky if some of these lead-free electronic products
outlast the manufacturer's warranty period-- regardless of whether they
are:
* In continuous use.
* In intermittent use.
* Sitting idle.
OR
* Still in the original, unopened box!
Some problems that are showing up with lead-free solders and platings,
that have been almost unknown for over 40 years with lead-bearing
solders and platings, are:
* Tin whiskers, causing short circuits.
* Tin pest (tin plague, tin leprosy, tin disease), causing opens when
the solder turns to dust at temperatures below 13 degrees C.
* Sensitivity to physical shock, causing opens when a product is
dropped even a short distance onto a hard surface.
* Kirkendall voids, causing opens.
* Conductive anodic filaments (CAF), causing shorts *inside* printed
circuit boards.
I bought myself a new computer shortly after Christmas, and I don't plan
to buy any more new electronics for myself or my businesses -- unless I
absolutely have to -- until at least July 2007. By then we may know
whether lead-free electronics are worth a darn in any environment. Or
maybe the Europeans will repeal the RoHS Directive after enraged
consumers have lynched some of the legislators who enacted that
misbegotten law...
John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, SM IEEE
dBi Corporation
Robust Electronic Design, Inc.
http://www.dbicorporation.com/
(Author of Robust Electronic Design Reference Book, Volumes 1 & 2)
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