Key role of Ti 2 SnC surface oxides in tailoring interfacial diffusion behavior and electrical contact properties of Ag-based composites

Abstract To clarify the role of Ti2SnC surface oxides in the arc erosion resistance of Ag-based electrical contacts, a pre-oxidation strategy is employed to construct a controllable oxide layer at the Ag/Ti2SnC interface. Results show that pre-oxidation induces surface decomposition of Ti2SnC, leading to the in-situ formation of a TiO2-dominated oxide layer, and promoting the diffusion of Sn into the Ag matrix. Although such interfacial reconstruction decreases the initial density, tensile strength, and electrical conductivity, it enhances local solid-solution strengthening and increases interfacial hardness. After 10,000 arc cycles, the pre-oxidized Ag/Ti2SnC@TiO2 composite exhibits lower mass loss, average arcing time, and arc energy. Combined with the post-erosion surface morphology, the results suggest that the preformed oxide interface regulates interfacial diffusion behavior, which further affects arc-root attachment and migration, thereby suppressing localized arc action and molten Ag splashing. This study reveals the role of Ti2SnC surface oxides in regulating interfacial structure and arc erosion behavior, providing insights into the interfacial design of Ag/MAX-phase electrical contact materials.