Hi Zoran - Many of the users in the ANSIJ-STD-003 PWB solderability committee who have experience with immersion Au/Ni finishes have reported that a "good" immersion Au/Ni finish should last 12 months under typical storage conditions. The critical part of the equation seems to be finding a finish supplier understands their immersion gold chemistry and that does a good job of process control. Also take a look at "Fine Pitch Surface Mount Technology Assembly with Pb free low Residue Solder Paste", I. Artaki, Soldering and Surface Mount Technology, May 1995, page 27 - it may be helpful. Good Luck. Dave Hillman Rockwell Collins [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: ASSY:Au/Ni Coated Boards Author: [log in to unmask] at ccmgw1 Date: 5/28/97 9:08 PM Dear Technetters We have some printed circuit boards with gold over nickel coating which are experiencing solderability problems, ie very poor wetting. I have heard that this may be due to nickel migration through the gold over time. The boards are approximately 6 Months old. Is there a particular shelf life for this type of coating before we need to dump the boards?. Regards Zoran Raich Process Engineer NetComm (Aus) Ltd (+612) 9878 7394 [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************