No abstract

Amount of Bi 2 Se 3 has significant role in controlling thermoelectric properties of n-type Bi 2 (TeSe) 3 material. In this study, effects of Se alloying amount in Bi 2 (TeSe) 3 thermoelectric materials fabricated by high-energy ball milling and spark plasma sintering were studied and compared with other fabrication methods. Amount of Bi 2 Se 3 (5%, 10%, 15%, and 20%) did not have any significant effect over fabricated powder size, grains of consolidated bulks, and mechanical properties; however, electrical properties and thermoelectric efficiency were noticeably influenced. Both carrier concentration and carrier mobility decreased with increase in Se amount. In total, 20% Se alloying was effective in improving thermoelectric figure of merit ZT value by almost 40% compared with only 5% Se alloying.

<p>The recent rise in applications of thermoelectric materials has attracted interest in studies toward the fabrication of thermoelectric materials using mass production techniques. In this study, we successfully fabricate <italic>n</italic>-type Bi₂Te_2.7Se_0.3 material by a combination of mass production powder metallurgy techniques, gas atomization, and spark plasma sintering. In addition, to examine the effects of hydrogen reduction in the microstructure, the thermoelectric and mechanical properties are measured and analyzed. Here, almost 60% of the oxygen content of the powder are eliminated after hydrogen reduction for 4 h at 360°C. Micrographs of the powder show that the reduced powder had a comparatively clean surface and larger grain sizes than unreduced powder. The density of the consolidated bulk using as-atomized powder and reduced atomized powder exceeds 99%. The thermoelectric power factor of the sample prepared by reduction of powder is 20% better than that of the sample prepared using unreduced powder.</p>