Measuring equipment and measurements of adhesive force between gold electrical contacts

This paper describes the apparatus to measure adhesive force between electrical contacts with micro-sliding and the measurements of adhesive force between gold electrical contacts by this measuring equipment. The electrical contact that is concerned in this paper is mounted on a cantilever supporting arm in a small electromagnetic relay. A straight back-and-forth sliding motion occurs on closed contacts when a relay suffers from an externally applied shock, or on contact follow of closing contact operation. Therefore, this apparatus is designed to give a straight back-and-forth sliding motion to closed electrical contacts. We investigated the measuring accuracy of this apparatus and measured the adhesive force between gold electrical contacts. The following results have been confirmed: 1) The error in determination of contact force from 19.6/spl times/10/sup -3/-1.47 N is less than 1%, 2) The error in measurement of adhesive force from 9.8/spl times/10/sup -3/-1.47 N is less than 1%, 3) At gold contacts under conditions of contact force (0.1-0.5 N), and the number 1-20 cycles and the amplitude (50 and 100 /spl mu/m) of straight back-and-forth sliding motion, the adhesive force measured by this apparatus has been illustrated to be influenced by the contact force, and the number and the amplitude of sliding motion.