The Influence of Grain Size Distribution, Metal Oxide Content, and Additives on Switching Behavior of Ag/SnO_2 in DC and AC Relays

摘要

This paper will present new findings and conclusions from a multi-year research program on Ag/SnO_2. Additional information on this program was presented previously at the 52nd IRSTC 2004. The current phase of work focused on investigating the influence of three separate parameters on the switching behavior of DC and AC relays. The parameters considered included: the grain size and dispersion of the components, the metal oxide content, and the In_2O, content. For each case considered, the load type and current were varied. In automotive relays, materials with larger oxide particles achieve equivalent or better results. In the case of general purpose relays, the maximum life in regards to welding and erosion is achieved with a large metal oxide content (12%). Welding resistance and erosion behavior are counteracted less effectively by reducing the amount of In_2O_3 and using larger metal oxide particles. It has been determined that in general, a very high degree of oxide particle dispersion is only advantageous at low currents like those are switched in general purpose relays.