Microstructure and Arc Erosion Resistance of Ti2alx (X=C, N) Reinforced Ag-Based Electrical Contact Materials

Abstract

A group of MAX phases including Ti2AlC and Ti2AlN are candidate reinforcements of Ag-based electrical contact materials. In this work, the interfacial reaction, resistivity, hardness and arc erosion resistance of Ag/Ti2AlX (X=C, N) were investigated comparatively. In both Ag/Ti2AlX, obvious interfacial reaction occurred, characterized as the deintercalation of Al from Ti2AlX and the diffusion of Ag into Ti2AlX. The negative reaction enthalpies by first principal calculations confirmed the interfacial reactions of Ag/Ti2AlX, while the higher vacancy formation energy of Al in Ti2AlN elucidated the slighter reaction of Ag/Ti2AlN. The sintering of Ag/Ti2AlX decreased the hardness and conductivity, and the slighter reaction led to larger decrease in hardness and smaller decline in conductivity. Moreover, Ag/Ti2AlN showed superior arc erosion resistance, with less evaporation of Ag and oxidation of Ti2AlC. This were attributed by less vulnerability of mildly decomposed Ti2AlN, less resistance heat and its easier dissipation during erosion, as a result of the better electrical and thermal conductivity.

Keywords: Ti2AlN and Ti2AlC, Ag-based composites, interfacial reaction, Physical properties, Arc erosion