SYNTHESIS OF Cu1.6Bi4.6S8 COMPOUND FOR THERMOELECTRIC APPLICATION

Abstract

In this work, Cu_1.6Bi_4.6S₈ thermoelectric compound was synthesized using high energy milling and heat treatment. The starting mixture include Cu, Bi and S elemental powders at the stoichiometry ratio of the formula Cu_1.6Bi_4.6S₈ were ball milled in a planetary ball mill and heat treated in an electric furnace. The results shown that after 10 hours of milling, a compound identified as Cu_3.21Bi_4.79S₉ was formed. The 16h milled powder was heat-treated at 350, 400 and 450ºC for 1 hours at a heating rate of 8 ºC/minute, XRD of the annealed powder reveals that the Cu_3.21Bi_4.79S₉ obtained fully transformed into Cu_1.6Bi_4.6S₈ after being heat treated at 400ºC. Meanwhile, Bi₂S₃ was found in the powder being annealed at 350ºC. The 5h milled powder was also annealed at 400ºC for 1 hours at a heating rate of 2 and 8 ºC/minute, XRD analysis show that Cu_1.6Bi_4.6S₈ was also formed in the heat-treated powder with the heating rate of 2 ºC/min.