Electrical characteristics for novel titanium oxide and carbide enhanced Ag-based contact materials: experimental and simulation

In this study, the Ag-8 wt.%TiO 2 and Ag-8 wt.%TiC contact materials were fabricated by powder metallurgy. The electrical contact tests were performed for 10,000 operations at 24 V/20 A. The microstructure, eroded morphology, surface roughness, arc behavior, material transfer and welding behavior were characterized, and the arc erosion mechanism was discussed based on the first-principal calculation for interfacial properties of Ag/TiO 2 and Ag/TiC heterostructure. The experimental results show that the Ag-8 wt.%TiC contact material presents lower and stable arc-duration, less mass loss, slighter welding, smaller crater/pit and lower surface roughness than the Ag-8 wt.%TiO 2 contact material, indicating much better arc erosion resistance. The first-principal calculation reveals that the larger electron transfer and better interfacial bonding occur at the Ag/TiC interface as compared to the Ag/TiO 2 interface, thus promoting arc migration, and reducing the violent flow and splashing of Ag-8 wt.%TiC contact material. Furthermore, it is found that the dynamics behavior of molten pool remarkably influences the phase distribution at the eroded surface and the roughness, causing the change in arc characteristics, material transfer and welding.