Hello, I am looking for some information either from experience or papers on what causes brittle solder joints. We have immersion gold over nickel and use eutectic solder paste. Board material is high-temp FR4. I would like to know: 1. How many heat cycles a solder joint will tolerate without becoming brittle. Is there a temp that a solder joint becomes brittle and the crystalline structure changes (as in steel tempering)? 2. What would be the definition of a heat cycle (would it be reaching 183 C or something else)? 3. What is a safe temp to have boards at during a stress testing.. any information or a contact to find information would be greatly appreciated. Thanks in advance for your help, Christina Piasky ([log in to unmask]) Sequent Computer Systems ############################################################## 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. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################