Abstract
The formation process of a Mg2Si-MnSi1.73 thermoelectric device made by mechanical alloying (MA) and pulsed current sintering was investigated.
MA was performed in a planetary ball mill using two elemental powders of each material. The MA powders were consolidated by pulsed current sintering method. The Seebeck coefficient of Mg2Si sintered at 773 K under 250 MPa was −366 μV/K at room temperature. However, the electric conductivity of the obtained Mg2Si was very small and about 0.04 S/m. Therefore copper wires were mixed in order to improve the electric conductivity of Mg2Si. When the quantity of Cu wires was 5 vol%, the Seebeck coefficient kept the same value in spite of increasing electric conductivity to 0.65 S/m. A thermoelectric device with a laminated structure of Mg2Si and MnSi1.73 was made by sintering with a Cu sheet placed at the boundary surface of Mg2Si and MnSi1.73 and was not broken during cutting process.
