The term rust may be used slightly differently UK/US, so I dredge up from memory what I was taught sometime ago in last century England: Strictly only iron can rust, but it is more than just iron oxide. It is a dynamic mixture of iron oxides and water which perpetuates itself as long as there is a supply of oxygen in damp conditions. Non ferrous metals don't rust therefore but they may tarnish. Phosphorus is not a metal, so it can neither rust nor tarnish to oxide, it actually burns quite vigorously. As mentioned below generally oxides do not conduct, the only one I can think of off hand that does is silver. Some oxides in conjunction with the base metal can make rectifiers so conduct in one direction only. In iron oxide terms old fashioned cast iron drainpipes used to accidentally act as simple radio receivers and re-transmitters due to this rectification phenomenon. Confession time: when I get asked this sort of "I ought to/used to know this basic sort of stuff" question, or need to know enough to ask a harder one myself, I quite often visit www.howstuffworks.com You can ask almost anything you like and it usually comes back quickly with the answer you were thinking of. More importantly it assumes almost no prior knowledge so you can understand it. Best regards Mike Fenner Applications Engineer, European Operations Indium Corporation T: + 44 1908 580 400 M: + 44 7810 526 317 F: + 44 1908 580 411 E: [log in to unmask] W: www.indium.com Leadfree: http://Pb-Free.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of <Peter George Duncan> Sent: Friday, November 30, 2001 12:19 AM To: [log in to unmask] Subject: Re: [TN] Rusty Hi, Kathy, Rust is a very poor conductor, as anyone with a rusty car and wiring trouble can testify. Corrosion on battery terminals can ruin a connection, and where oxidisation is deliberate, such as in anodising of aluminium, electrical conductivity is poor to non-existant, depending on the thickness of the oxide layer. Peter Duncan Kathy Kuhlow <Kathy@BTW-IN To: [log in to unmask] C.COM> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Sent by: Aero/ST Group) TechNet Subject: [TN] Rusty <[log in to unmask] ORG> 11/30/01 01:55 AM Please respond to "TechNet E-Mail Forum." I was asked a question today and I can't seem to find the answer. I think I know but I need more then a gut feel. Is rust conductive, just a by product, or both? The materials we were discussing are phosphorus, bronze, iron. Thanks in advance. Kat (See attached file: TEXT.htm) [This e-mail is confidential and may also be privileged. If you are not the intended recipient, please delete it and notify us immediately; you should not copy or use it for any purpose, nor disclose its contents to any other person. Thank you.] --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------