Recently we discover this incredible property of some metal alloys, concretely some kind normally employed for soldering electronic parts. In the old ages of electronics, a straightforward metal for soldering was tin due to its low melting point and good conductivity. However, after some time and in certain conditions, the solder joint or other tinned surfaces started to raise like little visible hairs to the eye, creating a path to electricity and with it, malfunctions and equipment damage. Other “hairs” do work like an antenna and morphologically seem one!
One of the solution was to add lead, and this was the most used alloy for soldering during ages until the recent RoHS directive from Europe trying to prevent the environmental contamination caused by lead due to the massive quantity of it in the electronic industry.
Even when the exact cause of these little formations is only hypothesized so still unknown, other alloys appeared in the scene. Adding silver or copper was proven useful as a method to mitigate this very strange property. As the RoHS directive was widely adopted, there are chances of having these modern alloys without lead in some devices that you frequently use. Believe it or not, probably some spots in the electricity path are right now growing tiny metal hair! According to some papers in the subject, not every contemporary lead free alloy was proven 100% safe to “metal whiskers”.