I am interested in information and experience with solder for high temperature applications for a program I am researching. For this specific example, the unit is a ceramic substrate with silver palladium pads. Temperature conditions are as follows: --Blob top cure is 3 hours at 130?C for three hours --Thermal Shock: Un-powered temperature cycling from -40?C to 140?C, 30 minutes at each temperature, with a 10second transition time (goal is 1000 cycles) --Powered temp. cycling, 95% humidity, from -40?C to 105?C with one hour transition time, 3 hour dwell time for 1000 hours. Units that were built previously used a solder paste with a 179?C eutectic temperature. The solder joints failed over time in testing. What is the best solder paste to use for this application (reflow process, standard components)? Some documentation recommends a high tin content (95%) but discussions have suggested that at these temperatures the tin becomes brittle over time. High lead content solders (88%) have been suggested, but these have such a high reflow temperature (>300?C) that standard SMT components (SOIC's) cannot stand these temperatures. I appreciate any suggestions and information Ed Holton Hella Electronics 313-414-0944 [log in to unmask] ############################################################## 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 ##############################################################