MIL-STD-889 Donald Durett Engineering Manager Astrolab Inc. 4 Powderhorn Drive Warren, NJ 07059-5105 Tel: 732-560-3800 Fax: 732-560-9570 -----Original Message----- From: Dave Hillman [mailto:[log in to unmask]] Sent: Tuesday, February 04, 2003 3:12 PM To: [log in to unmask] Subject: [TN] Galvanic Corrosion Testing Hi TechNet! I am on a quest for some information and hoping the minds of TechNet can send me charging off in the right direction. Rockwell Collins has been very active in implementing the new immersion pwb finishes (immersion tin, immersion silver, ENIG). The implementation has been very successful with few "bumps in the road" being encountered. However, one question has arisen that; a) as a metallurgical engineer I should have anticipated and b) you would think someone else would have solved already. The question is " Is there a galvanic corrosion issue with the use of either ENIG or immersion silver pwb surface finishes and the aluminum chassises/enclosures"? As background, there is very little of the pwb finish in intimate contact with the aluminum chassis with most of the contact being aluminum standoff posts contacting a circular mounting pad on the pwb. I have spent a number of hours looking for some type of galvanic corrosion test which I could run to determine if either immersion silver or ENIG finishes would be an issue. The two environments I have the most interest in are temperature/humidity and salt air. I am tentatively going to run an 85C/85%RH and an ASTM salt fog exposure on some mockup test sets to see if I have any reactions. Has anyone run such a test or can anyone direct me to a Mil STD or ASTM standard which deals with galvanic corrosion of contacting dissimilar metals? Thanks in advance. Dave Hillman Rockwell Collins [log in to unmask] --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------