Microstructures and Thermoelectric Properties of Melt-Spun ZnxSb3 Ribbons

Melt-spun ZnxSb3 ribbons were fabricated with weight compositions of x = 3.6, 3.9, and 4.2 through a single-wheel process and were annealed for 2 h at 673 K. The microstructures of the ribbons were investigated using transmission electron microscopy, together with energy-dispersive x-ray analysis. The main structure consisted of β-Zn4Sb3 phase, which mainly coexisted with ZnSb phase for x < 4 and with Zn phase for x > 4. The analyzed composition of the β-Zn4Sb3 phase deviated from the stoichiometric composition of 4:3 for all the ribbons. Nanosized voids and zinc inclusions were randomly distributed throughout the β-Zn4Sb3 phase. The thermoelectric characteristics of the ribbons were revealed by measuring the Seebeck coefficient, electrical conductivity, power factor, dimensionless figure of merit, and thermal conductivity. The power factor and dimensionless figure of merit increase with increasing x and temperature because either the electrical conductivity or Seebeck coefficient increases.