Erosion Behavior of Several AgCdO Materials-A Comparison Between Actual Contactors and a Testing Machine

Contact materials, several AgCdO and one AgZnO, prepared either by internal oxidation or by means of powder metallurgy are tested on a welding-erosion testing machine. Results are then compared with those obtained on actual contactors, operating in AC4utilization category. This information is taken into account for ranking the materials according to the erosion criterion which ultimately determines the life duration of many switching devices. Because of the present state of knowledge, a straight relationship is not established between physical and metallurgical characteristics of contact materials and their behavior when used in low-voltage industrial control products. Nevertheless for sintered materials, a thermal test whose results seem to be in good correlation with their resistance to the erosion resulting from electric arcs in contactors is proposed.