Witam,
Cytuje ciekawy artykul z listy PCADa a dotyczacy RoHSa:
Lead free components are more of a risk than the PCB.
Tin whisker growth has been documented in areas without solder. Most of them are on the order of 100u inch.
Here is a lot of information, and lots of pretty pictures.
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Most of the tin whiskers are being found on component leads and form at the bend points.
IBM and Sony are petitioning to exempt all ICs with lead spacing less than
25 mils from RoHS.Since most lead free components are some form of white tin, the engineers need to worry about the parts more than the PCB plating. Some manufacturers are already 100% lead free, so you may be at risk now.