Hi Rudy! First, I don't have an exalted position - I'm just a grunt working in production! What is your definition of corrosion? Oxidation is can be classified as corrosion depending on the metal (e.g. iron) but oxidation of tin or tin/lead is not corrosion. There is a number of sources of EMF tables that are more than just deionized water based - they work quite well in a number of industrial applications to predict potential galvanic issues. Solder does have better corrosion resistance than pure tin but to suggest that there is a "profound" difference implies that the hundreds of tin plated aluminum electronics housing in the field are undergoing corrosion problems which is just not true. I guess we'll agree to disagree on this issue. Dave Hillman Rockwell Collins [log in to unmask] [log in to unmask] on 11/05/99 08:49:42 AM To: [log in to unmask], David D Hillman/CedarRapids/Collins/Rockwell@Rockwell cc: Subject: Tin vs. Tin/Lead solder Dave: With all due respect to your exalted position in this area.... I have seen many many problems in the fabrications area caused by having pure Tin, as compared to having Solder, especially if the it is true solder, i.e. that it is the true alloy, which seems to have profoundly better corrosion resistance than merely "plated solder", which is nothing other than discrete chrystals of Tin and Lead. (Should I note that we make money and have products which have a life only because they solve this issue... in selected situations:-) And ignoring any ostensibly authoritative EMF tables, which I have found to be effective in academia, and few other places (because they are meaningful only when the electrolyte is deionized water), the solder seems to have much better resistance to corrosion than pure Tin, and especially plated Tin, which seems especially "active". If what I am saying is true, that Solder is much more passive than pure Tin, you have the makings for a seriously pumping galvanic cell, which should need only an electrolyte to crank up, and deliver you Tin oxide all over the pure Tin plating... And remember, free advice is often worth what you pay for it... Regards, Rudy Sedlak RD Chemical Company ############################################################## 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. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################