Emission and arc studies of contacts with metal-oxide inclusions

This paper reports studies of contact admixtures effects on recovery voltages of contact pairs when admixtures have a form of multiple inclusions of some metal oxides introduced into standard contact material CuCr 50/50. The breakdown and recovery voltage studies of these materials were carried out at a simulating circuit with load current up to 300 A and frequencies 50 kHz - 120 kHz. Grains of alumina, and hafnium, lithium and lanthan oxides were used as inclusions. CuCr 50/50 with small tungsten chips was used as reference material. Statistical characteristics of recovery voltages were obtained for these materials and some promising compositions were selected for future studies.