Joe, the gold fingers (pads) porosity requirement is to ensure the connector
reliability for card edge connector applications. The pad has a critical zone
where connector spring contacts the pad. If it is not pore free, corrosion is
likely to develop that may cause intermittent or opens.

Second issue arises when card is inserted into edge connector. Again if the
pad edges have porosity and hence corrosion product, it will get dragged into
contact area during insertion causing connector reliability. I have seen that
occur many times in product assurance testing for reliability.

Third, the wear of gold plating is also affected by porosity again leading to
contact reliability issues.

There are many excellent papers on the subject.The two of these are given
below for reference. If you need further assistance or wish to discuss,
please call.


Pratap Singh
RAMP Labs
(512) 255-7820

REFERENCES
1."Corrosion Through Porous Gold Plate" by S.J. Krumbein, June 1969, pp89-98,
IEEE transactions on Parts, Materials and Packaging.
2."Corrosion of Porous Gold Plating in Field and Laboratory Environments" by
WH Abbot, pp 72-75, November 1987, Plating and Surface Finishing.