Effects of Oxygen Content and Grain Size on Thermoelectric Properties of Bi-Te Sintered Compounds
Year: 1999
Type: article
Abstract: Influence of oxygen content and grain size on the thermoelectric properties of hot pressed bismuth-tellurium based compounds has been investigated. Bismuth, tellurium, antimony and selenium powders were mixed to the stoichiometric compositions of (Bi, Sb)2Te3 for p-type and Bi2(Te, Se)3 for n-type, respectively. The powder mixtures were ball-milled in acetone and consolidated by hot pressing at 733 K for the p-type and 773 K for the n-type compound in an argon or hydrogen atmosphere. Sintering in a hydrogen atmosphere provided a lower oxygen content, particularly for the p-type compound. Coarser grain size (2-10 μm) was observed for the p-type sintered samples while the n-type samples exhibited a finer grained microstructure (about 1 μm). Seebeck coefficient, electrical resistivity and thermal conductivity of the sintered samples were measured at room temperature. The p-type compound exhibited dependence of the figure of merit (Z value) on grain size while the figure of merit of the n-type compound could be expressed as a function of oxygen content. The obtained maximum Z values were 2.5×10−3 K−1 for both of the p-type and n-type compounds.
Authors: Satoru Matsuo, Mari Yonetsu, Hirofumi Tashiro, Kazunori Nakano, Ken-ichi Takagi
Institution: Toyo Kohan (Japan)
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2606363676