Hi Terry, In PCBs, palladium is not barrier but instead nickel (Check Electroless Ni-Immersion Au). Palladium is used to activate the copper inorder for Nickel (used as barrier) to plate, you can notice that every Process in Electroless Ni-Au have an Activator (which is usually palladium). You can't plate copper traces with out palladium activation. In components such leads, they use Palladium (Ni-Pd) to preserve solderability of the Nickel surface, they also used palladium (small amount) not as barrier but to prevent cracking on leads after bending. If you use palladium as barrier it is too expensive. Hope this helps thanks Jonathan A. Noquil R&D FSCB, CEBU, Phils. Terry Exell <[log in to unmask]> on 06/27/2000 03:50:33 PM Please respond to "\"TechNet E-Mail Forum.\" <[log in to unmask]>, Terry Exell" <[log in to unmask]> To: [log in to unmask] cc: (bcc: Jonathan A Noquil/Cebu/Fairchild) Subject: [TN] Palladium query Fellow TechNetters, Can someone please enlighten me as to the purpose of a Palladium Barrier on components / PCBs. Best regards Terry Exell BAE SYSTEMS, Plymouth, UK ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ############################################################## ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################