The Failure Mode and Lifetime of Static Contacts

This paper describes the failure mode due to corrosion at the contacting surfaces of static contacts in connectors and mechanical wiring connections. Copper static contacts with no mechanical separation fail to maintain electrical continuity when temperature-cycled from 20 to 200°C. Electron diffraction analysis and microscopic inspection show that this failure mode is due to growth of Cu2O film over all or part of the contacting surfaces. The lay? between the contact members is estimated to be 15 to 3250 A thick and the lifetime of the copper static contact at light loads is proportional to load.