Hi

I have used both electrloytic palladiium plated leads and boards with a great
amount of success.  The palladium should be on the thin side, less than
20micinches [0.5 micron] since there is some mechanism with the thicker
platings that causes cracking of the solder joint at the palladiium solder
interface.   It has been attributed by some to the formation of many
intermetallics that are formed with both tin and lead and the palladium.
Other researchers have blamed it on the formation of the heavy intermetallics
leaving behind the brighteners and other co-plated materials in the deposit.
These then form a weak layer in the structure and the joint cracks.  Whichever
mechanism is correct, do not use thick platings.  I have had mixed results
with the electroless palladiums and are more likely to see the appearance of
the poor flow at the tin/lead palladium interface surface.  Other times the
surface seemed to be rough and would not wet well.  I have heard of good
results with the electroless Pd,  perhaps it is the reducing agent or reducing
method that makes a difference.

Phil Hinton

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