The Effects of Sintering Conditions and Processes on the Thermoelectric and Tribological Properties of High Manganese Silicide Mn4Si7

Abstract

Triboelectric nanogenerator as new energy technology needs to develop new triboelectric semiconductor materials with excellent electrical transport properties and friction properties for better electric output performance. High manganese silicide Mn4Si7 bulks were prepared from Mn powders and Si powders at 1273 K for 1 h. The residual Si phase and MnSi phase coexisted in the primary sintered Mn4Si7 compacts. The fine Mn powder obtained from mechanical pulverization and secondary sintering can accelerate the formation of Mn4Si7 bulks. MnSi disappeared and slight amount of Si phase remained in the secondary sintered Mn4Si7 bulks. Due to the slight decrease in the resistivity, ZT of Mn4Si7 bulks reached 0.43 at 813 K. The thermal conductivity of the secondary sintered Mn4Si7 compact increased due to the pulverization of the primary Mn4Si7 bulk and the growth of crystal grains. The thermoelectric properties of Mn4Si7 compact are reduced after heat treatment. Secondary sintering can increase the density of Mn4Si7 compact. For the friction property of Mn4Si7, secondary sintering and heat treatment can reduce the coefficient friction and mass loss of primary sintered Mn4Si7 compact. Based on the excellent thermoelectric properties and low wear loss at low loads of Mn4Si7, it is possible to be employed as new triboelectric materials for triboelectric nanogenerator. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.