Abstract:

Ag-based electrical contact plays a key role in low-voltage switches, which is intended to substitute the traditional and toxical “universal” contact of Ag/CdO. As a new kind of two-dimensional carbide material with good electrical conductivity and thermal conductivity, Ti₃C₂T_x, a representative of MXenes has showed exceptional potential in various fields, including being the reinforcement phase in electrical contact materials to substitute for the toxic CdO. In this work, we successfully prepared Ag/Ti₃C₂T_x composite by powder metallurgy. Phase and microstructure of the Ti₃C₂T_x and Ti₃AlC₂ were characterized, and their properties, such as electrical resistivity, microhardness, machinability, tensile strength, and anti-arc erosion performance were investigated and compared. The Ag/Ti₃C₂T_x has a resistivity of 30×10 ^-3 μΩ·m, 29% lower than that of Ag/Ti₃AlC₂ (42×10 ^-3 μΩ·m) and excellent machinability with intermediate microhardness (64 HV), showing broad application prospect as non-toxic electrical contact materials. Its improved conductivity is mainly attributed to the metallicity of Ti₃C₂T_x itself, the microstructural features, endowed by the deformability of Ti₃C₂T_x. However, the tensile strength (32.77 MPa) of Ag/Ti₃C₂T_x is inferior to that of Ag/Ti₃AlC₂ (145.52 MPa) due to lack of Al-Ag interdiffusion. The anti-arc erosion performance of Ag/Ti₃C₂T_x is also unmatchable with Ag/Ti₃AlC₂ due to absence of Al layer. Although the arc erosion resistance of Ag/Ti₃C₂T_x needs to be further improved uptill now, the significantly improved electrical conductivity makes it a potential substitute of current toxic Ag/CdO material. All results of this work provide an exploration direction for developing new environmentally friendly electrical contact material in the future.

Key words: electrical contact material, MAX phase ceramic, MXene, electrical conductivity, mechanical property, anti-arc erosion performance