Improving arc erosion resistance of AgNi electrical contact material by a three-dimensional graphene network

Abstract

The electrical contacts are subjected to severe arc erosion with advance towards high power and miniaturization of electrical devices, and the increasingly stringent requirements are put forward for electrical contact materials. To enhance the arc erosion resistance of AgNi electrical contact materials under large current conditions, the Ag-10Ni electrical contact material reinforced by three-dimensional graphene (3D-Gr) was fabricated by the combination of in-situ growth of Gr on Ni particles surface and powder metallurgy in this work. Electrical contact performances were evaluated using an electrical contact test system. The microstructure and eroded morphologies were characterized, the influence of 3D-Gr on the physical and electrical properties was analyzed, and the arc erosion mechanism was discussed as well. The results demonstrate that the incorporation of 3D-Gr simultaneously enhances the electrical conductivity, hardness and arc erosion resistance of Ag-10Ni electrical contact material. As compared to the Ag-10Ni electrical contact material without Gr, the electrical conductivity and hardness of the 3D-Gr reinforced Ag-10Ni electrical contact material are increased by 7.2 % and 10.9 %, respectively. Moreover, the Ag-10Ni electrical contact material with 3D-Gr exhibits lower arc energy, shorter arc duration and reduced mass loss. The superior arc erosion resistance can be ascribed to the formation of 3D-Gr, which offers a continuous heat-transferred pathway, mitigates the oxidation of Ni and reduces the splashing of the molten pool.