Electro-mechanical properties and welding characteristics of Ag/MoS2, Ag/WS2, Ag/CNTs and Ag/CdO materials for high-DC current contact applications

The optimisation of contact materials emerges as a cornerstone for reliable functionality of high-speed DC circuit breaker. Ag/CdO is widely used despite its RoHS non-conformity. To overcome this issue new materials are requested. We have prepared Ag/MoS2, Ag/WS2, Ag/Carbon-nanotubes composite materials and investigated their structural, mechanical, electrical and thermal properties. These materials have been used in switching operation tests on a laboratory-scale fully instrumented model of circuit breaker, under a maximum current load of 12 kA. Welding and sticking tendencies were examined. A relationship between the microscopic variables, the occurrence of welding events and their strengths was established.