Improved arc erosion resistance of Ag/SnO2 composites fabricated by Ag melt-infiltration in the SnO2 skeleton

The typical Ag-SnO2 contact materials in which SnO2 dispersing in the Ag matrix suffer a poor arc erosion resistance because the individual SnO2 particles segregate and form a SnO2-rich layer under repeated arcing. Here, we introduce an architectured Ag/SnO2 composites in which individual SnO2 particles are bonding into a skeleton, fabricated by a novel method: (i) creating a porous SnO2 matrix by sintering SnO2 powders with NaCl space-holders, (ii) then infiltrated by Ag melt in the air. 95% relative density is achieved for the Ag/SnO2 composites. The microstructure evolution during the sintering and infiltration are investigated. 10,000 times make-and-break operations are conducted to evaluate the arc erosion resistance of the architectured composite, the temperature rise of the prepared Ag-60vol.%SnO2 composite decreases similar to 90% compared with the particle dispersed composites. The microstructure of the arc-erased layer is analyzed and reveals that the SnO2 skeleton effectively suppresses the formation of the SnO2-rich layer, providing good arc erosion resistance and the potential for long lifetime contacts.

Automated summary

The novel method of creating an architectured Ag/SnO2 composite by bonding individual SnO2 particles into a skeleton improves arc erosion resistance compared to traditional dispersed composites, showing better performance.