In a message dated 98-03-10 17:36:16 EST, you write: << Has anyone any information on barrel cracking associated with the use of electroless nickel (EN) under a gold finish. We have a problem with 0.3 mm via's in FR4 multilayer boards cracking after thermal shock at 260°C. We have other problems with this board but is there any information on what effect EN has under these conditions ? >> Could you please supply a little more information about these parts that show barrel cracks? The standard electroless nickel thickness is 0.1 to at most 0.2 mils in a barrel that should be plated to 1.0 mils or more with copper. (Or perhaps your spec on vias is to allow as little as 0.5 mils of copper - please clarify). The copper electroplate should control the thermal performance in your case - are barrels cracking if they are HASL or OSP? Electroless nickel should exhibit a high tensile strenghth on its own - even if the ductility is not as good as electroplated copper. Are you saying that the nickel only is cracking? The gold should be so thin as to have no effect on thermal performance. Dennis Fritz MacDermid, Inc - Waterbury CT ################################################################ 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 ################################################################