Jack: In addition to the galvanic effect, you have to worry about fretting corrosion. The tin that is exposed to the air will oxidize and produce tin oxide. The micro-vibrations found in any office environment are suffient to allow growth of this oxide surface between the gold and the tin-lead surface. Eventually this corrosion will to an intermittent or an open situation. It is extremely difficuilt to detect this problem since removing the device wipes it clean of the oxide and reinsertion shows no problem. Bell Laboratories did some extensive studies in the early 1980s and this was then carried over as a requirement to the Bellcore Physical Design Requirements. Harry \\'''''// (o o) @----oOO---------(_)----------------@ | Harry O'Halloran | | DSC Communications Corporation | | 1000 Coit Road | | Plano, TX 75075-5813 | | Phone: (214) 519-3916 | | [log in to unmask] | @--------------------------oOO------@ | __ | __ | | | | | ooO Ooo ______________________________ Reply Separator _________________________________ Subject: Re: assy:compatability gold vs tin/lead Author: [log in to unmask] at SMTPLINK Date: 5/22/96 1:13 PM Good morning Jack! I have several articles in my references that describe both acceptable use and disastrous use of tin/lead pins in gold sockets. I think the key word you used is "potential". In the right environment (moisture - not necessarily water) you will have problems because of the galvanic effect of tin on gold. If things stay dry then you may have no problems. For a battery to form you need two dissimilar metals and an electrolyte - take away one of the three and you avoid problems. Look at your environment and see if moisture would be a concern. Also look at the ASM Metals Handbook Vol. 13 Corrosion for additional information. Dave Hillman Rockwell Collins [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: assy:compatability gold vs tin/lead Author: [log in to unmask] at ccmgw1 Date: 5/22/96 11:11 AM We have instances where tin/lead coated pins are inserted into gold plated sockets, etc. Components even have gold/tin-lead or gold/tin interfaces, such as an IC socket with a gold contact with a tin sleeve. Mil-Std-889B indicates gold as being incompatable with tin or tin/lead. Has anyone looked into this issue and is there a potential for corrosion formation and associated problems? Again, I just refereing to mechanical contact ( not soldering ). Thanks, Jack Tippit Wilcox Electric [log in to unmask]