We plate tin-lead over nickel regularly, either immediately or after another layer of resist. We're running a Watts bath (nickel chloride, nickel sulfate, boric acid) rather than sulfamate. The activation of the nickel surface before the tin-lead plating is critical. If the nickel plate has been dried, there's an initial PC-455 bath to clean the surface, then the steps are water rinse, 40% hydrochloric etch, rinse, 10% fluoboric etch, rinse, tin-lead plating. Once started from nickel to tin-lead, the timings are tightly controlled, certainly no long dwells in the rinses or etches. Steve Axdal [log in to unmask] Tom Bresnan wrote: > All: > > Is there a preferred nickel I should be trying to plate solder on top > of? We're struggling with plating tin lead on top of nickel and it's > subsequent reflow after soldermask. Anyone have any suggestions? We're > seeing dewetting and I'm wondering how many others out there are > trying to do this. We currently use a nickel sulfamate bath, if that > has any bearing... I'm not sure of activators and such, but if you > think it's important, I'll find them. > > Thanks in advance all... > > Regards > > Tom Bresnan > [log in to unmask] > > PS. Please respond direct to me as well as to the forum. I'm presently > disconnected from the service. snip-------------------------- ################################################################ TechNet E-Mail Forum 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://jefry.ipc.org/forum.htm) for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################