As all know, more suppliers are switching to lead-free
component finishes.  More parts will be coming in with gold, and 
some will have pure tin.

If more parts come in with gold, we are faced with doing more
hot-solder dip, unless we can determine a safe proportion of gold
in an assortment of types of solder connections, and we can
measure the amount of gold on the component leads.

Likewise, if parts come in with pure tin, we may have to hot-solder
dip to minimize risk of whiskers.  Problem is that we buy some
parts from distributors, and unlike gold, we can't tell just by looking
whether the finish is tin or tin/lead.

What kind of instrumentation is available?  Does x-ray fluorescence
work to determine gold thickness?  Can it be used to determine
whether a finish is tin or tin/lead?

Is EDX an option?  It can detect the presence of lead, but can it
be used to determine gold thickness?

Are EDX or XRF available in tabletop or hand-held units?  What do
they cost?  Any particular sources that anyone can recommend?

Joe Kane
BAE SYSTEMS Control
Johnson City, NY

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