Hans, the only non-destructive method for this measurment is XRF X-Ray
Flouresence.  With your smallest collimator, you can get close, but
never
the Knee.  Suffice it to say, the coating is pretty skinny at the knee.
Probably 20 to 40 micro inches.

These smaller numbers as measured with XRF are suspect at best.  What is
it measuring? Free T/L above the intermetalic? Only the intermetalic
penetration? Both?  I guess SEM and a very carefully prepared x-section
could tell.

But, if you are having problems associated with a thin coating at the
knee, the place to attack the problem is in drill and copper plating.

A correctly de-burred hole will break the hard edge and provide more
surface area for plating.  This in turn will hold more SN63 from HAL.

Generally, its hard to stack much of anything on a hard corner.  A
little radius goes a long way, eh?

PS: Copper thickness is greatly under rated in its influence on HAL
thickness potential.

If you have specific questions not covered here, feel free to contact me
directly.

Mark Simmons, V-Score Central

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