>Tin whiskers has nothing to do with it. This is not accurate. Tin whiskers are a well-known problem resulting from pure tin coatings (although the mechanism i

>Tin whiskers has nothing to do with it. This is not accurate. Tin whiskers are a well-known problem resulting from pure tin coatings (although the mechanism is not well understood) and lead has historically been added to mitigate their growth (among other benefits). From Wikipedia: "Traditionally, lead was added to slow down whisker growth in tin-based solders." [0] From NASA: "No single mitigation technique provides effective protection against whisker formation except the addition of 3% or more of Pb by weight" [1] "Suggestions for Reducing Risk of Tin Whisker Induced Failures...1. Avoid the use of PURE TIN plated components if possible...Alloys of tin and lead are generally considered to be acceptable where the alloy contains a minimum of 3% lead by weight...Although some experimenters have reported whisker growth from tin-lead alloys, such whiskers have also been reported to be dramatically smaller than those from pure tin plated surfaces and are believed to sufficiently small so as not to pose a significant risk for the geometries of today's microelectronics." [2] [0] https://en.wikipedia.org/wiki/Whisker_(metallurgy) https://en.wikipedia.org/wiki/Whisker_(metallurgy) [1] https://nepp.nasa.gov/whisker/reference/tech_papers/2011-kostic-Pb-free.pdf https://nepp.nasa.gov/whisker/reference/tech_papers/2011-kos... [2] https://nepp.nasa.gov/whisker/background/index.htm https://nepp.nasa.gov/whisker/background/index.htm