Long term storage of PCBs with trace amounts of sulfur in wrapping
     or container have indicated attack of tin/lead <solder>. (I believe
     the lead oxidizes and effects the wettability.) I believe it also
     effects nickel/gold finishes also. At least bondable gold I do know
     requires sulfur free (actually VCI) packaging.
        I have not seen any reports on this. Maybe someone from the
     independent test lab houses could better point you in a data 
     direction.
     
     Groovy
______________________________ Reply Separator _________________________________
Subject: Sulphur contamination
Author:  [log in to unmask] at SMTPLINK-HADCO
Date:    4/25/96 12:42 PM


I am interested in finding out potential causes of contamination of PCB,s 
with sulphur. What typical fabrication or assembly processes may introduce 
this contaminant to the board. What are the long term potential effects of 
sulphur contamination and are there any studies I could reference.
     
Any suggestions or papers would be appreciated.