Effects of Al doping on phase transition and thermoelectric properties of β-Zn4Sb3

Abstract

In this paper, Al-doped Zn4Sb3 compounds (Zn 1-xAlx)4Sb3 (x=0,0.0025,0.005) were prepared by using the method consisting of high-temperature melting, rapid cooling and hot-pressing(300°C) under a high pressure. (Zn 1-xAlx)4Sb3 has been investigated by low-temperature internal friction (IF) measurements and DSC respectively, the IF measurements show that there is internal friction-peak between 258K and 263K. The peak intensities become lower for higher frequencies but the peak positions are fixed with increasing frequency. It have the typical IF features of phase transition. DSC measurements show that the phase transition is reversible. With the increase of Al doping the phase transition enthalpy increased, the apparent activation energies increased from about 214KJ/mol to 238KJ/mol, prompted Al doping could partially inhibit the phase transition. In addition, high-temperature thermoelectric properties of (Zn1-xAl x)4Sb3 were investigated. The results indicated that resistively and thermo power of the doped compound (Zn 1-xAlx)4Sb3 (x≠0) increased remarkably as compared to that of Zn4Sb3, the power factor of (Zn 1-xAlx)4Sb3 increased between room temperature and 420K, but decreased in the hot parts. © 2011 Published by Elsevier Ltd.