Ag/MAX electrical contacts show great potential for low-voltage switching applications. However, the influence of MAX phase structural characteristics on interfacial diffusion, material transfer behavior, and nanomechanical evolution of Ag/MAX composites under arc erosion remains unclear. In this study, Ag/Ti₃AlC₂ and Ag/Ti₂SnC composites were fabricated, and their interfacial evolution, material transfer behavior, and nanomechanical degradation during arc erosion were systematically investigated. The results reveal that the structural differences between Ti₃AlC₂ and Ti₂SnC significantly affect the arc-induced degradation behavior of Ag/MAX composites. Due to the weaker Ti-Sn bonding, Ti₂SnC exhibits higher interfacial reactivity at elevated temperatures, promoting Sn diffusion into the Ag matrix and enhancing interfacial bonding, thereby suppressing molten Ag migration and reducing material loss. In contrast, Ti₃AlC₂ with stronger Ti-Al bonding maintains higher structural stability during arc erosion, resulting in less structural decomposition and superior nanomechanical retention after erosion. This work establishes the relationship between MAX phase bonding characteristics, arc-induced interfacial diffusion, material transfer behavior, and nanomechanical evolution, providing insights into the design and optimization of high-performance Ag/MAX electrical contact materials.

To clarify the role of Ti₂SnC surface oxides in the arc erosion resistance of Ag-based electrical contacts, a preoxidation strategy is employed to construct a controllable oxide layer at the Ag/Ti₂SnC interface. The results show that preoxidation 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 discharge cycles, the preoxidized Ag/Ti₂SnC@TiO₂ composite exhibits lower mass loss, shorter average arcing time, and lower 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.

Al-containing MAX phase ceramic has demonstrated great potential in the field of high-performance low-voltage electrical contact material. Elucidating the anti-arc erosion mechanism of the MAX phase is crucial for further improving performance, but it is not well-understood. In this study, Ag/Ti₃AlC₂ electrical contact material was synthesized by powder metallurgy and examined by nanoindentation techniques such as constant loading rate indentation, creep testing, and continuous stiffness measurements. Our results indicated a gradual degradation in the nano-mechanical properties of the Ti₃AlC₂ reinforcing phase with increasing arc erosion times, although the rate of this degradation appeared to decelerate over arc erosion times. Specifically, continuous stiffness measurements highlighted the uneven mechanical properties within Ti₃AlC₂, attributing this heterogeneity to the phase’s decomposition. During the early (1–100 times) and intermediate (100–1000 times) stages of arc erosion, the decline in the nano-mechanical properties of Ti₃AlC₂ was primarily ascribed to the decomposition of Ti₃AlC₂ and limited surface oxidation. During the later stage of arc erosion (1000–6200 times), the inner region of Ti₃AlC₂ also sustained arc damage, but a thick oxide layer formed on its surface, enhancing the mechanical properties and overall arc erosion resistance of the Ag/Ti₃AlC₂.