Microstructures and thermal properties of Sn–Bi–Pb–Zn alloys as heat storage and transfer materials.

Low-melting-point alloy has the characteristics of high thermal conductivity, low solidus temperature and the wide range of use temperature, which is a potential heat transfer medium. The microstructure and thermal properties of Sn–Bi–Pb–Zn alloys as heat transfer and storage material were investigated in this paper. The phase compositions, microstructure and thermal properties were investigated by X-ray diffusion (XRD), electron probe microanalysis (EPMA) and differential scanning calorimeter (DSC) analysis, respectively. The results show that the phases of Sn–Bi–Zn and Sn–Pb–Zn alloys are mainly eutectic formed by solid solution, while the formation of Pb₇Bi₃ intermetallic compounds decreases the melting point of Sn–Bi–Pb and Bi–Pb–Zn. The thermal properties of the zinc-containing alloys are better than that of Sn–Bi–Pb, but the weight of the zinc-containing alloys significantly reduces above 900 °C. As the density, specific heat capacity and thermal diffusivity change with temperature and physical state, the thermal conductivity of the alloys first decreases and then increases. These results demonstrate the feasibility of using low-melting alloys as the heat transfer and storage material. [ABSTRACT FROM AUTHOR]