Direct synthesis by hot pressing and thermoelectric properties of Zn4Sb3

Direct synthesis by hot pressing has been used in order to produce high efficiency Zn₄Sb₃ bulk specimens. Single phase Zn₄Sb₃ with 98.5% of theoretical density were successfully produced by direct hot pressing of elemental powders containing 1.2 at.% excess Zn. Phase transformations in this alloy system during synthesis were investigated using DSC, XRD and SEM. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of other studies. Transport properties at room temperature were also evaluated. Seebeck coefficient increases and electrical conductivity decreases with increasing temperature up to 600 K. Thermoelectric power factors in directly synthesized Zn₄Sb₃ up to 600 K were comparable to published data, leading to an estimated figure of merit value of 1.2 at 600 K. Direct synthesis by hot pressing provides an optional processing route in this material.