Investigation of interfacial characteristics and arc erosion behavior of Ag-Ni-GNPs electrical contact material: simulation and experiment

The incorporation of GNPs into Ag-Ni contact material is expected to be an effective approach to improve the electrical performance. However, the formation of Ag/carbon and Ni/carbon interfaces may introduce a potential concern, and its influence on the arc erosion behavior of Ag-Ni contact materials remains unclear thus far. To tackle this issue, the interfacial characteristics for Ag/Ni/GNPs were comparably investigated via first-principle calculation, and the arc erosion behavior of Ag-8 wt%Ni contact materials with 0-0.4 wt%GNPs additions was validated at 24 V/20 A and 36 V/28 A. It is found that the Ag/Ni has the best interfacial bonding among all of interfacial systems. Nevertheless, Ni/GNPs interface exhibits much weaker bonding than Ag/Ni interface, but it remains 2-3 times stronger than Ag/GNPs interface. The experimental results show that the eroded morphology and arc behavior remain stable with increasing GNPs content at 24 V/20 A, and the welding force decreases significantly at 0.4 wt%GNPs addition. At 36 V/28 A, however, the welding resistance has an apparent aggravation at 0.4 wt%GNPs along with the serious degradation eroded morphology and arc duration. To explain this phenomenon, the self-reinforcing degradation effect of arc erosion is proposed. The seriously damaged morphology can result in the increase of arc duration, and the arc action with a longer time in turn promotes the deterioration of the morphology. The interfacial characteristics serve as the fundamental cause, whereas the electrical load acts as the direct driving force for the self-reinforcing degradation of arc erosion.