Hi, What actually accounts for the large black patches on pads when the technology goes wrong? Are these sulphates? Regards and it is quiet difficult to find somebody (except the >supplier) who has production experience. I had some experience of work with >electroplated silver coatings. The major problem of silver surfaces is >tarnishing. The solderability of silver is good but significantly degrades >when sulfides form on the surface. Under high temperature, the sulfides react >with oxygen and form sulfates. One of the solutions to this problem is >protection of silver with anti-tarnishing coatings (BTA, etc.). However, all >these coatings are extremely fragile and can be easily destroyed. It was also >observed that the thin coatings (thinner than 40 uin) degrade much faster. >This problem was solved by placing an intermediate nickel layer. > > >Chris > >################################################################ >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 the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 >################################################################ > > > ################################################################ 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 the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################