Tin is a fascinating material with all kinds of interesting properties. My personal favorite: the crying of tin. Bend a piece of tin close to your ear and you can hear the crystal lattice beg for mercy against impending metal fatigue. When it stops crying the piece has torn.
One of the problems is that the onset of tin whisker growth is stochastic. In other words, we can't predict when they will start growing, it's random. Which means they can start growing in a day, a week, a month or three years.
If I remember correctly, once they start growing the growth rate is reasonably constant and can reach many millimeters per year.
If that doesn't sound bad at all, keep in mind that fine pitch integrated circuit pads in modern electronics could be in the order of 0.2 mm apart. Which means a tin whisker that grows at a rate of 10 mm/year could bridge that gap in about one week.
I could be wrong on this, but it is my opinion we will eventually discover the RoHS initiative backfired and we generated more consumer waste than we every had before RoHS. I still have my 30+ year old HP-41C calculator (as well as a small collection of other HP calculators). They all work perfectly. They don't have lead-free solder. I doubt any RoHS era calculators will be able to survive that long and still work. In other words, we are likely filling our trash dumps at a faster rate than ever before due to RoHS.
There’s been plenty of work, but It’s a hard one to elucidate physical mechanisms for because they are super rare in terms of the number of potential initiation sites... You have to get lucky if you want to observe the material state before the whisker formed
It’s become more of a practical problem since the restrictions on leaded solders, since lead-free solder alloys seem more prone to whisker formation...
Yes. A startup where I worked built an internet appliance that had a socketed chip modem. One failed mysteriously, pulling it out and testing it, it worked, plugging it in, it failed. Looking closely at the area below the socket a tin whisker was pointed straight up from one of the socket pins. Almost impossible to see unless you looked at it at just the right angle.
Yes, I've seen RoHS-related whisker issues in production hardware, although not related specifically to lead-free solder. These whiskers [1] appeared on the body of a PCB-mounted TNC jack from Amphenol, a US-based vendor.
It's very upsetting to see this happen to your own hardware, just because some EU bureaucrats believe that long-lasting electronic products are a bad thing rather than a good thing. Fortunately, 6 years down the road, it appears to have been a one-time incident.
Lead leeching into the soil and water supply is a very, very bad thing. Eventually, even long-lasting electronics must be disposed of, and if it contains significant quantities of lead, it poses a risk of poisoning the environment.
Those "EU bureaucrats" are protecting their children, and by extension yours through a sort of regulatory herd immunity, from lead toxicity.
Lead leeching into the soil and water supply is a very, very bad thing. Eventually, even long-lasting electronics must be disposed of, and if it contains significant quantities of lead, it poses a risk of poisoning the environment.
Yeah, right. Where are the numbers? If lead "leeches" out of solder and into the water table, it happens in microscopic quantities on geologic timescales.
Getting lead out of gasoline made sense. Solder and plating, no. At less than 0.66 grams of solder based on tin content alone [1], one iPhone built with 63/37 eutectic lead solder would contain less lead than about 20,000 car batteries. Last I checked, we're still poisoning your children with those.
You are very seriously underestimating the effect of lead in the environment. If this is the sort of thing that gets people upset at the EU bureaucrats then I'm all for it. ROHS free products have longevity on par with what was delivered before, yes, there have been some minor issues but in spite of the 'sky is falling' initial response that simply didn't happen.
Lead sucks, don't get me wrong. But it still has valid industrial uses. I just Googled for the stats, and we apparently still sell about 100 million car batteries a year in North America alone. Which seems crazy high, but at least they almost all get recycled since the market demand still exists.
We should be doing that for electronics, too. Right now "recycling" electronics means sending it to China where some kid takes it apart with a blowtorch, so yeah, I'm sure they appreciate RoHS. That doesn't make it a net win for the electronics industry or for humanity in general.
Admittedly, you're right about reliability increasing over time, and I'll further admit that I expected a different outcome entirely. By making manufacturing more difficult and expensive, RoHS forced everyone to pay strict attention to their processes, and that tends to result in better products. The Amphenol thing is a glaring exception.
