naa a22 4500 510801943 CHVBK 20180411092758.0 cr unu---uuuuu 180411e20130701xx s 000 0 eng 10.1007/s11664-012-2418-6 doi (NATIONALLICENCE)springer-10.1007/s11664-012-2418-6 Crystallographic, Thermoelectric, and Mechanical Properties of Polycrystalline Ba8Al x Si46− x Clathrates [Elektronische Daten] [Hiroaki Anno, Masahiro Hokazono, Ritsuko Shirataki, Yuko Nagami] The Al content dependence of crystallographic, thermoelectric, and mechanical properties is reported for polycrystalline Ba8Al x Si46−x (nominal x=15 to 17) clathrates prepared by combining arc melting and spark plasma sintering methods. The elastic constants and the coefficient of thermal expansion (CTE), which are also important properties for designing thermoelectric devices, are presented. Powder x-ray diffraction, scanning electron microscopy, and energy-dispersive x-ray spectroscopy (EDX) indicate that the typeI clathrate is the major phase of the samples but impurity phases (mainly BaAl2Si2, Si, and Al) are included in the samples with high Al contents. The actual Al content x determined by EDX ranges from approximately 14 to 15. The absolute value of the Seebeck coefficient increases and the electrical conductivity decreases as the Al content increases. The changes in Seebeck coefficient and electrical conductivity are explained in terms of the dependence of the carrier concentration on the Al content. The elastic constants and the CTE of the samples depend weakly on the Al content. Some of the properties are compared with reported data of single crystals of Ba8Al16Ge30, Ba8Ga16Ge30, Sr8Ga16Ge30, silicon, and germanium as standard references. The effective mass, Hall carrier mobility, and lattice thermal conductivity, which govern the transport properties, are determined to be ~ 2.4m 0, ~ 7cm2V−1s−1, and ~ 1.3Wm−1K−1, respectively, for actual Al content x of about 14.77. The thermoelectric figure of merit ZT is estimated to be about 0.35 at 900K for actual Al content x of about 14.77. TMS, 2013 Clathrate nationallicence Ba8Al x Si46− x nationallicence thermoelectric properties nationallicence coefficient of thermal expansion nationallicence elastic modulus nationallicence elastic constant nationallicence Anno Hiroaki Department of Electrical Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-dori, 756-0884, Sanyoonoda, Yamaguchi, Japan aut Hokazono Masahiro Department of Electrical Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-dori, 756-0884, Sanyoonoda, Yamaguchi, Japan aut Shirataki Ritsuko Department of Electrical Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-dori, 756-0884, Sanyoonoda, Yamaguchi, Japan aut Nagami Yuko Department of Electrical Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-dori, 756-0884, Sanyoonoda, Yamaguchi, Japan aut Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/7(2013-07-01), 2326-2336 0361-5235 42:7<2326 2013 42 11664 https://doi.org/10.1007/s11664-012-2418-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11664-012-2418-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Anno Hiroaki Department of Electrical Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-dori, 756-0884, Sanyoonoda, Yamaguchi, Japan aut NATIONALLICENCE 700 1- Hokazono Masahiro Department of Electrical Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-dori, 756-0884, Sanyoonoda, Yamaguchi, Japan aut NATIONALLICENCE 700 1- Shirataki Ritsuko Department of Electrical Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-dori, 756-0884, Sanyoonoda, Yamaguchi, Japan aut NATIONALLICENCE 700 1- Nagami Yuko Department of Electrical Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-dori, 756-0884, Sanyoonoda, Yamaguchi, Japan aut NATIONALLICENCE 773 0- Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/7(2013-07-01), 2326-2336 0361-5235 42:7<2326 2013 42 11664 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 510363342 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer