David,
     
     The only test I am aware of involves nitric acid vapor and 
     eletrographics.  Insure your gold plating is within 5-10 millionths 
     and never greater than 50 millonths.  Any less than 5 millionths Au 
     with improper immersion plating will cause the Au to be porous, 
     in-turn, oxidizing underlying copper and not allowing the flux to 
     properly clean.  A high Au concentration, greater than 50 millionths, 
     causes poor bond strength.
     
     The concern of porosity should not be a concern, since millions of 
     SIMMS, DIMMS and bareboards go into products every day with no contact 
     problems.  If you are using NiAu as an alternative surface finish, 
     I've conducted several ineternal environmental tests with NiAu, OSP 
     and HASL with no problems.  If you are having problems with 
     conductivity at the connector region, investigate the connector or the 
     PCB supplier and set in place the above recommendation.
     
     If it still concerns you; 2 pores per contact tab on 10% of the 
     contact tabs, and no more than 1 pore on each of the remaining tabs 
     (BS 9762)  
     
     or reference
     
     IEC-326 and prepare to discuss porisity in-depth with your chosen 
     vendor.
     
     


______________________________ Reply Separator _________________________________
Subject: Plating specification 
Author:  [log in to unmask] at halsic_ccsmtp
Date:    10/19/95 11:20 AM


     There are plating specifications and test methods for gold over nickel
plating on printed circuit board edge connectors. Verifying plating 
thickness is straight forward but what pass/fail criteria are used in the
industry for porosity of gold over nickel? How many pores per CM*CM are allowed?
     Any sources of information/specifications would be appreciated.
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