Anthony,
This has been all covered before, so you should really check the TechNet
archived stuff. Suffice to say, that the silver is preferred over the tin
because of the modern versions of either, the silver ones have been around
longer than the tin ones and more people have had better success with the
silver than the tin. Now this does not in itself say silver is better than
tin, so you tin providers shouldn't bother roasting me!
The term "white " is used as this is the usual chemical designation for the
room temperature allotropic modification of tin. This structure of tin has
the usual beneficial structural properties of tin that one would like to
see. The other form - gray tin, forms at the transition temperature of 13.2C
and below. This form is a powdery gray as opposed to the "shiny",
"whiteness" of normal metallic tin. Gray tin is quite rare as additions of
fairly small amounts of other elements retard the change from white to gray.

I'm sure other Technetters can add more, if they are so inclined. :)
regards,


Bev Christian, PhD,
Director of Electronics Manufacturing
XLTEK
cell: (905) 334-2993
ph: (905) 829-5300 x 295
fx: (905) 829-3561
<mailto:[log in to unmask]>

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