Thermoelectric Properties of Mg2Si Produced by New Chemical Route and SPS

Inorganics

Wilfried Wunderlich³  Yoshihito Suzuki¹  Naoto Gibo¹  Takahiro Ohkuma¹  Muayyad Al-Abandi¹  Masashi Sato¹  Atta Ullah Khan² 

[1] Applied Chemistry Department, Faculty of Engineering, Tokai University, Kitakaname 4-1-1, Hiratsuka 259-1292, Japan;National Institute for Materials Science (NIMS), International Center for Materials Nanoarchitecture. (MANA), Tsukuba 305-0044, Japan;Material Science Department, Faculty of Engineering, Tokai University, Kitakaname 4-1-1, Hiratsuka 259-1292, Japan

关键词: thermoelectrics;    silicide;    hydrogen sorption;    microstructure;    power generation;    Seebeck coefficient;   

DOI  :  10.3390/inorganics2020351

来源: mdpi

【 摘 要 】

This paper reports about a new synthesis method for preparing Mg₂Si in an efficient way. The intermetallic Mg₂Si-phase forms gradually from a mixture of Mg and Si fine powder during exposure to hydrogen atmosphere, which reacts in a vacuum vessel at 350 °C. The resulting powder has the same particle size (100 µm) compared with commercial Mg₂Si powder, but higher reactivity due to large surface area from particulate morphology. Both types of powders were compacted by spark plasma sintering (SPS) experiments at 627, 602, 597, and 400 °C for 600 s with a compaction pressure of 80 MPa. The thermoelectric characterization was performed with low and high temperature gradients of ΔT = 10 K up to 600 K. The results confirmed a Seebeck coefficient of −0.14 mV/K for specimens sintered from both powders. The small difference in total performance between purchased and produced power is considered to be due to the effect of impurities. The best values were obtained for n-type Mg₂Si doped with 3% Bi yielding a Seebeck coefficient of −0.2 mV/K, ZT = 0.45) and electric output power of more than 6 µW.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.