Electrical contact characteristics of Ag-SnO₂ materials with increased SnO₂ content

The electrical contact characteristics including temperature rise, contact resistance and arc erosion rate of the Ag-SnO₂ materials with increased SnO₂ content were investigated during the repeated make-and-break operations. The thickness of arcing melting layer reduces by half and the arc erosion rate decreases more than 70% under 10000 times operations at AC 10 A with the SnO₂ content increasing from 15 wt.% to 45 wt.%, on one hand, temperature rise and contact resistance increase obviously but could be reduced to the same order of conventional Ag-SnO₂ materials by increasing the contact force. The microstructure evolution and the effect of SnO₂ on the arc erosion, contact resistance were analyzed.