Evaluation of Copper-Beryllium Contacts for High Current Density Pulsed Applications

Low-resistance metal-to-metal contacts, both static and sliding contacts, are of interest to many scientific and technical applications as magnetic confinement fusion, railguns, and electrical motors. In fusion applications, silver-coated copper contacts and low-current-density designs are preferred, while in other applications, high current densities are required. For high-pressure high-current-density sliding contacts, contact pairs such as aluminum/copper are preferred as in railguns, while for electrical motors, copper-copper alloys are preferred. Copper-beryllium alloy, C172, is investigated as static contacts for high-current-density pulsed-power applications. To subject the contacts to suitable current pulses and pressures, a special electrical contact assembly has been developed allowing contact pressures from 0 to 66 MPa and current densities from 62 to 263 kA/cm 2 . The contacts were studied under different current density pressure combinations with repeated 60- \mu \text{s} pulses in air, while current evolution and surface modifications were followed. Besides some surface oxidation, no evidence of other surface modifications like welding or surface melting were found.