Ralph Mowery wrote:



There is one other problem I have seen , not with solder, but tin plated
items. The tin "whiskers'. Probably will be a problem with the
tin/silver and no lead solder.
Pure tin solder, if not processed hot enough to anneal the Tin, can get REAL
bad. Part of the reason for the tin/silver solder is to reduce the whisker
formation, and it seems to work. I had some Xilinx chips which had pure tin
lead plating, and I was processing them at PbSn temperatures, and the LEADS,
not the solder joints, had whiskers at the bends in the leads, as this is
where the stressed tin was. Xilinx suggested hotter soldering temps.

Jon