THERMODYNAMICS OF THE STRUCTURAL-CHANGES IN THE LIQUID ZN-SB SYSTEM

The thermodynamic properties of Zn-Sb alloys were investigated by measuring the sound velocity and molar volume as functions of temperature and composition. Around the composition corresponding to the metastable solid compound Zn4Sb3, where the specific heat has large temperature dependence, the sound velocity increases quite steeply with increasing temperature, by contrast with the observation for most liquid metals. A similar variation has been found for the thermal expansion coefficient as a function of temperature. The unusual temperature variation of these thermodynamic parameters may be interpreted as being due to the rapid dissociation with increasing temperature of the ionic clusters 'Zn4Sb3' persisting in the liquid.