Steve, This sounds like a problem with nickel passivation, and your nickel seems a little on the thin side so the copper under- neath may be oxidizing as well. When soldering to nickel, a more active flux and/or higher reflow temperature is frequently required. Electroless gold is porous and will not keep the nickel underneath from oxidizing, especially during thermal excursions. Regards, Karl Sauter, Staff Engr. Sun Microsystems, Inc. karl.sauter@EBay,Sun.COM ----- Begin Included Message ----- Date: Fri, 06 Oct 95 10:46:40 EST From: "ETHIER_SA" <[log in to unmask]> To: [log in to unmask] Subject: soldering gold pcb,s X-Loop: [log in to unmask] We are having some problems soldering to an electroless gold over nickel card. specifics are: 5-10 microinches electroless gold over 20 microinches electroless nickel. .020 thick double sided smt card being soldered in a nitrogen covection reflow oven. components range from 0603-1206 passives, sot 23 devices, and a 25 mil ssop. Soldering is being done using Alpha 609 water soluble 63/37 paste with a fairly standard profile. Results thus far are that the joints are granular, cold appearing, with marginal wetting to both card and components. There are also numerous occurrances of voids/pinholes eminating from the lead pad interface. Any insights would be helpful in the areas of: Profiles Pastes Methods for checking incoming solderability of the cards. Any thoughts on optimal gold/nickel characteristics Thanks for the help. Steve Ethier Mgr. New Product Engineering Lockheed Martin Commercial Electronics Tel: 603-885-8432 ----- End Included Message -----