Fabrication of large sintered pellets of Sb-doped n-type Mg{sub 2}Si using a plasma activated sintering method

• Published in: Journal of solid state chemistry 2012-09, Vol.193
• Main Authors: Hayatsu, Yusuke, Iida, Tsutomu, Sakamoto, Tatsuya, Kurosaki, Shota, Nishio, Keishi, Kogo, Yasuo, Takanashi, Yoshifumi
• Format: Article
• Language: English
• Subjects: DOPED MATERIALS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MAGNESIUM SILICIDES; MATERIALS SCIENCE; SINTERING; THERMAL CONDUCTIVITY
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/J.JSSC.2012.07.008

Sb is known to be the most stable n-type dopant in Mg{sub 2}Si, whereas the reproducibility and sintering scalability of Sb-doped Mg{sub 2}Si has proved to be difficult. We have developed a metallic binder for the Sb-doped Mg{sub 2}Si sintering process. A remarkable benefit of the binder is that it enables us to reproducibly fabricate large sintered Sb-doped Mg{sub 2}Si pellets up to 30 mm in diameter with no internal cracks. For binder contents of 3-7 wt%, the observed power factor and thermal conductivity were identical to that of conventional Sb-doped samples, while excess binder degraded the TE properties. The binder mixture also plays a part in increasing the yield in the production of TE legs, up to 82% for 5 wt% Ni incorporation, as well as improving the hardness of the sintered sample. Incorporation of 5 wt% Ni binder affected an increase in the ZT value up to 0.97. - Graphical abstract: The sample of 30 mm in diameter is fabricated by using a Ni binder. Highlights: Black-Right-Pointing-Pointer We have developed a metallic binder for the Sb-doped Mg{sub 2}Si sintering process. Black-Right-Pointing-Pointer Sb-doped Mg{sub 2}Si pellets up to 30 mm in diameter with no internal cracks. Black-Right-Pointing-Pointer Incorporation of 5 wt% Ni binder affected an increase in the ZT value up to 0.97.