Letter 34042

Tin Whiskers - The Next Y2K Problem  

(2005)

Good legislation often has unintended consequence. Fortune has an article, the next Y2K problem in the making - tin whiskers short-circuiting critical equipment, an unintended consequence of lead-free environmentally friendly initiatives such as WEEE & RoHS. Any comment?

James Smallwood
electronics mfgr. - Moorestown, NJ, US

Indeed, pure metals are far more prone to whiskering than alloys. But tin whiskers have been studied for decades, their causes are well documented, and this issue is not new.

I'm concerned about the restrictions on cadmium and hexavalent chromium. Although these are miserable substances which we are getting out of the environment as rapidly as practical, I think we simply can't know what will happen in the long term to our airplanes and cars as we substitute zinc alloys for cadmium and trivalent chrome for hexavalent chromates. A related issue, not legislation induced, is that as electronics become smaller and smaller we find whiskering problems with other metals like zinc, too.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

I like to report back my research on recent development of tin whiskers.

Yes this is a 50+ years problem, however it is given a new life due to the following factors:
a)lead-free initiatives and consumers’ awareness
b)rapid miniaturization of electronics components more prone to short-circuit by tin whiskers

The problem of tin whiskers is further complicated by the fact:
a)tin whiskers growth mechanism is not fully understood
b)there is universally accepted test strategy to evaluate tin whiskers growth.

The WEEE and RoHS are EU legislations but have huge impact globally. The electronics industry worldwide, lead by NEMI is responding aggressively this issue, especially the mitigation strategy. NASA issued a prohibition order for pure tin plate electronics packaging.

I recommend the following sites:
a) NASA Goddard Space Flight Center maintain a comprehensive site on whiskers http://nepp.nasa.gov/whisker/
b) Fortune has an article, Tin Whiskers – The Next Y2K Problem. For the link to the article and discussion, goto http://www.materialsforum.net/bbs/viewforum.php?f=3

James Smallwood
- New Jersey

Thanks for the very interesting update, James. After reviewing your links, I rescind my previous response and agree with you that there is immediate potential for disaster, directly caused by the EU legislation. Apparently the fastest way to get lead out of tin-lead alloys was to simply "wish-away" the demonstrated advantage of tin-lead over pure tin, and apparently there has been so much pressure that people have succumbed and are doing just that.

Ted Mooney finishing.com Brick, New Jersey

I am a student at Vermont Technical College. I am writing a paper on tin whiskers. I was hoping some one could let me know about some of the latest developments conserning solving the problem of lead free solder and tin whisker growth on sensitive electronic components. At the least a push in the right direction would be apreciated

Sincerly Adam Auchmoody

Adam Auchmoody
Student - Vernon, Vt, USA

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