I stumbled upon this a couple of months ago and was truly fascinated, I'd never heard of this phenomenon despite formally studying electronics and radio etc over forty years ago, perhaps some of you have encountered this? This is another discussion and here is the forum that the UK guys began talking about this.

 

Probably related to the tin whisker problem which came up when lead was taken out of solder a few years ago.

https://www.maximintegrated.com/en/design/technical-documents/tutorials/5/5250.html

 

The problem was discovered in the 1940's. The solution was to add some lead to the tin solder.

Then the EU came along and made a decision to remove the lead. Who knows how many people were hurt or killed due their well intentioned, but flawed, decision. So what was old became new again... I think NASA and airline manufacturers are exempted from RoHS due to the potential risks.

https://en.wikipedia.org/wiki/Whisker_(metallurgy)

 

I stumbled upon this a couple of months ago and was truly fascinated, I'd never heard of this phenomenon despite formally studying electronics and radio etc over forty years ago, perhaps some of you have encountered this? This is another discussion and here is the forum that the UK guys began talking about this.

I still have the local OSHA on my case for using lead solder for equipment repairs in a 7/24 industrial environment on high voltage equipment where Tin Whiskers are a real problem for equipment that's been online for decades. I'm not giving in to the dull-side of unleaded solder.

The misguided fools just won't admit they made a huge mistake with the electronic RoHS (policy driven, not science driven) directive.

https://www.maximintegrated.com/en/design/technical-documents/tutorials/5/5250.html

Is Lead Really the Problem?
Changing pace just a bit, consider the lead question from a different perspective. How much lead is really being consumed each year? According to the International Lead and Zinc Study Group, worldwide usage of lead increased slightly in 2010 to 9.595 million metric tons from 8.966 million metric tons in 2009.4 (This increase is understandable, given the slowed economy in 2009.) Of that lead usage, 80% is consumed in lead-acid batteries. Note also that before the RoHS directive, only 0.5% was consumed in electronic solder and a mere 0.05% was consumed in electroplate for ICs!

What do all these statistics tell us? The 2010 usage of lead, in all applications, was approximately 21 billion pounds. Of that, 16.8 billion pounds was consumed in batteries and only about 10.5 million pounds would have been consumed in IC lead finish if the RoHS directive were not in force for electronics. By the way, the lead in lead-acid batteries remains exempt from the RoHS directive.
Recall that the expected environmental harm from lead in electronics was the impetus behind the RoHS legislative action. Lead was feared as a contaminant to groundwater. But many well-intentioned people overlook one important fact: elemental lead is not water soluble. Other sources concur: "Lead does not break down in the environment. Once lead falls onto soil, it usually sticks to the soil particles."5 When burned in an open-fire recycling operation, lead was feared to cause a poisonous vapor if inhaled. From NASA,6 the facts are:

An open-fire temperature is approximately 1000°C, but Pb boils at 1740°C.
Thus, the vapor pressure of Pb would be negligible, presenting little possibility of Pb vapor poisoning.
Workers who solder with SnPb do not have high Pb levels in their blood.

In the end, there is no evidence that lead in electronics presents a health risk or causes environmental harm. However, many of the proposed lead-free solutions do pose environment problems and many are much worse for the environment.