Hi Camille,

It would be inappropriate for us to respond to your question in this forum
but I will just briefly address the point about tin pest (the allotropic
transformation of high tin alloys from the  beta to the alpha form at low
temperatures).

I presented a paper reporting the Nihon Superior study of this phenomenon to
the recent IPC/JEDEC lead-free conference in San Jose.

The basic finding, which applies equally to all the high tin lead-free
solders, is that tin pest is effectively suppressed by the impurities which occur
naturally in standard purity tin (99.9%) so that if you make the lead-free
solder with standard tin it is highly unlikely that the phenomenon will occur.
Solder made with such tin should still be RoHS compliant by a factor of at
least 10.

Keith Sweatman
Nihon Superior Co. Ltd

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