Effect of Al atomic layer on the wetting behavior,interface structure and electrical contact properties of silver reinforced by Ti3AlC2 ceramic

Ti₃AlC₂ ceramic exhibits potential in Ag-based composite electrical contact materials, but its interface characteristic with Ag matrix remains unexplored. In this work, sessile drop experiment is carried out to investigate the high-temperature wetting behavior of molten Ag with Ti₃AlC₂. Stable Ti₃AlC₂ is hardly wetted by molten Ag below 1000 °C(contact angle of 148.5°), but the wettability of Ag/Ti₃AlC₂ improves with the increasing temperature(final 14° at ～1130 °C). In contrast, the Ti₃C_2, a MXene with Al layer removed from its parent Ti₃AlC₂, exhibits inferior wettability with Ag(final 56.5° at ～1130 °C). Wetting mechanism of Ag/Ti₃AlC₂ is proposed on the basis of the interfacial structure and chemical composition. Increasing temperature accelerates dissociation of Ti₃AlC₂, and outward-escaping Al reacts with Ag to form interface layer with a composition of Ag_4.86Ti_8.66AlC_7.59, Ag also diffuses along Ti₃AlC₂ grain boundaries and forms gradient reactive products(Ag–Ti–Al–C), which promotes their wettability. Finally comprehensive properties of Ag/Ti₃AlC₂ and Ag/Ti₃C₂ are compared. Al–Ag interdiffusion slightly decreases the electrical conductivity of Ag/Ti₃AlC₂ bulk material, but strengthen the interface bonding of composite and promote the viscosity of the molten pool, leading to the superior mechanical and anti-arc erosion properties. Absence of Al–Ag interdiffusion does remarkably improve the electrical conductivity of Ag/Ti₃C₂ bulk materials, but lack of Al layer damages the mechanical core and wettability with Ag, resulting in a drastic decrease of anti-arco erosion property.