A request forwarded from NIST- ______________________________ Forward Header __________________________________ Subject: Ideas for alloys for use in switch contact Author: [log in to unmask] at _internet Date: 8/21/95 6:48 PM I have a client who is looking for a copper or copper alloy to use in a switch-type assembly. The flat, slide contact is half-hard ETP copper.The bowed, fixed contact is a strip of Alloy 195. The force on both contacts, when closed, is 160 grams. Contact travel is about 3.2mm. Contact area varies from 0.4mm x 1.9mm to .8mm x 1.9mm. Voltage across contacts is 1 - 12 VDC. Current is 1 - 30 ma. Life expectancy of assembly is about 30,000 cycles. Problem is that contacts must be self-wiping. Assembly may stand for weeks without use. Oxide buildup has to be wiped off contact by other contact to make the contact. This causes wearing of both surfaces, resulting in ridges, which rapidly causes increased resistance across the contacts. Phosphor-Bronze and conductive lubricants have been suggested but not yet tried. In order to remain competitive, cost of solution must be as low as possible. Exotic materials and Rube Goldberg devices for cleaning the contacts are out. The key words here are 30,000 - 50,000 life cycles and cheap. Reply to: Bob Weller, CNYTDO, 1201 E. Fayette St. Syracuse, NY, 13210. Phone: (315) 425-5144 FAX: (315) 475-8460 E-mail: [log in to unmask] Please reply to the sender at the address above. If you reply by email, please send me a copy. Thanks in advance. - Charlie Rosenberg, TECnet, 4 Colby St. Room 153, Medford, MA 02155 E-mail: [log in to unmask] Tel: (617) 627-3818 Fax: (617) 623-1427