Thermal conductivity and microstructure of Bi-Sb alloys

Abstract

Four Bi-Sb alloys with compositions Bi79.6Sb20.4, Bi56.9Sb43.1, Bi39.8Sb60.2, Bi18.6Sb81.4 have been investigated regarding the microstructures and thermal properties. The microstructure was examined by scanning electron microscopy with energy-dispersive X-ray spectrometry. The light flash method was applied to determine thermal diffusivity and to obtain thermal conductivity in the temperature range 25 to 150??, while the indirect Archimedean method was used for determination of densities of the investigated Bi-Sb alloys. The obtained results have shown that the density of the studied alloys decreased monotonically with increasing the antimony content. On the other hand, the specific heat capacity of Bi-Sb alloys increased with the increase in the antimony content as well as with increasing the temperature. Thermal diffusivity of the alloys increased slightly with increasing the temperature. Thermal conductivities of the examined Bi-Sb alloys were determined to be in the range of 3.8 to 7 W m-1 K-1, which is lower than thermal conductivities of pure bismuth and antimony. The results obtained in this work represent a contribution to better knowledge of the thermal properties of Bi-Sb alloys, which are of key importance for determining the possibility of their practical application.