FABRICATION OF A NOVEL SILVER-BASED ELECTRICAL CONTACT COMPOSITES AND ASSESSMENT OF ITS MECHANICAL AND ELECTRICAL PROPERTIES

The electrical contactors play a crucial role in closing the circuit in many power distribution components like overhead lines, underground cables, circuit breakers, transformers, and control systems. The failure in these components mainly occurs due to the break-down of contactors due to the continuous opening and closing action of contacts. Silver (Ag)-based oxide contact materi-als are widely used in practice, among which silver tin oxide (AgSnO2) is most common. An attempt is made in increasing the performance of AgSnO2, by adding Tungsten Oxide (WO3) in various weight proportions, thus finding the optimal proportion of AgSnO2WO3 to have increased mechanical and electrical performances. All the composite samples are fabricated in-house using powder metallurgy process. The assessment of physical and electrical properties namely, density, hardness, porosity, and electrical conductivity, showed that 90%Ag-8.5%SnO2-1.5%WO3 composite yielded superior results. With help of morphological tests, wear characteristics are also investigated, which showed that 90%Ag-8.5%SnO2-1.5%WO3 composite has a wear coefficient of 0.000227 and a coefficient of friction of 0.174 at an optimized load of 10 N and sliding velocity of 0.5 mm/s.