naa a22 4500 51080196X CHVBK 20180411083359.0 cr unu---uuuuu 180411e20130701xx s 000 0 eng 10.1007/s11664-013-2585-0 doi (NATIONALLICENCE)springer-10.1007/s11664-013-2585-0 Grain-Oriented Ca3Co4O9 Thermoelectric Oxide Ceramics Prepared by Solid-State Reaction [Elektronische Daten] [Kohei Obata, Yasunori Chonan, Takao Komiyama, Takashi Aoyama, Hiroyuki Yamaguchi, Shigeaki Sugiyama] We studied a method to enhance the degree of grain orientation of Ca3Co4O9 thermoelectric oxide ceramics. Ceramic specimens were prepared by solid-state reaction with different growth conditions. Large-grained Ca3Co4O9 powders were obtained by using "heavy-calcination” and "moderate-grinding” steps before pelletizing, and these large-grained powders contributed to the enhancement of the degree of orientation. Scanning electron microscopy (SEM) observation results showed that plate-like crystal grains were stacked up in layers for the heavily calcined ceramics, while no such anisotropic structure was found for those that were lightly calcined. x-Ray diffraction (XRD) analysis also indicated that the specimen obtained by heavy-calcination and moderate-grinding steps had a high degree of (002) orientation. The effect of the heavy-calcination and moderate-grinding steps was clearly evidenced by the electrical resistivity ρ. The electrical resistivity ρ at 700°C for the higher-oriented ceramics was 73% of that for the lower-oriented ceramics. Since ρ was reduced without deterioration of the Seebeck coefficient S, the power factor (S 2/ρ) at 700°C for the former was increased by 29% compared with that for the latter. TMS, 2013 Ca3Co4O9 nationallicence thermoelectric oxide nationallicence solid-state reaction method nationallicence large-grained powder nationallicence grain-oriented ceramics nationallicence electrical resistivity nationallicence Obata Kohei Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuchi, 015-0055, Yurihonjo City, Akita, Japan aut Chonan Yasunori Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuchi, 015-0055, Yurihonjo City, Akita, Japan aut Komiyama Takao Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuchi, 015-0055, Yurihonjo City, Akita, Japan aut Aoyama Takashi Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuchi, 015-0055, Yurihonjo City, Akita, Japan aut Yamaguchi Hiroyuki Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuchi, 015-0055, Yurihonjo City, Akita, Japan aut Sugiyama Shigeaki Akita Industrial Technology Center, 4-11 Arayamachi-Sanuki, 010-1623, Akita City, Akita, Japan aut Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/7(2013-07-01), 2221-2226 0361-5235 42:7<2221 2013 42 11664 https://doi.org/10.1007/s11664-013-2585-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11664-013-2585-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Obata Kohei Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuchi, 015-0055, Yurihonjo City, Akita, Japan aut NATIONALLICENCE 700 1- Chonan Yasunori Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuchi, 015-0055, Yurihonjo City, Akita, Japan aut NATIONALLICENCE 700 1- Komiyama Takao Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuchi, 015-0055, Yurihonjo City, Akita, Japan aut NATIONALLICENCE 700 1- Aoyama Takashi Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuchi, 015-0055, Yurihonjo City, Akita, Japan aut NATIONALLICENCE 700 1- Yamaguchi Hiroyuki Department of Electronics and Information Systems, Akita Prefectural University, 84-4 Tsuchiya-Ebinokuchi, 015-0055, Yurihonjo City, Akita, Japan aut NATIONALLICENCE 700 1- Sugiyama Shigeaki Akita Industrial Technology Center, 4-11 Arayamachi-Sanuki, 010-1623, Akita City, Akita, Japan aut NATIONALLICENCE 773 0- Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/7(2013-07-01), 2221-2226 0361-5235 42:7<2221 2013 42 11664 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer