Effects of Annealing Temperature on the Thermoelectric Properties and Microstructure of Ag0.6Pb18Sb5Te20

Abstract

Keywords: vacuum arc furnace, thermoelectric materials, thermoelectric properties, figure of merit, ZT PbTe and Sb 2 Te 3 , two of the most common thermoelectric materials, have stable mid-and high-temperature thermoelectric properties. Both can be tuned as either N-type or P-type semiconductors. The figure of merit (ZT) values of the PbTe and Sb 2 Te 3 thermoelectric materials currently available on the market are around 0.8 and close to 1, respectively. In this study, Pb 18 Sb 5 Te 20 was used as a substrate and Ag was then added to form an Ag 0.6 Pb 18 Sb 5 Te 20 alloy. A comparison of thermoelectric properties between test pieces annealed at temperatures of 200, 400, and 600 °C and unannealed ones was conducted. The results revealed that the Ag 0.6 Pb 18 Sb 5 Te 20 alloy annealed at 600 °C had the best thermoelectric properties. The experimental methods used in this study included the preparation of bulk material using vacuum arc melting, X-ray diffration (XRD) analysis, a comparison with the Joint Committee on Powder Diffraction Standard (JCPDS) database to confirm the face-centered rhombohedral crystal structure, and a study of thermoelectric properties such as the Seebeck coefficient, thermal conductivity, and resistivity. The objective is the improvement of the material thermoelectric figure of merit ZT.