Title :
Effect of powder treatment by mechanofusion process on thermoelectric properties of FeSi2 system
Author :
Kita, Takuji ; Nogi, Kiyoshi ; Nagai, Hiroshi ; Kohno, Mizuki
Author_Institution :
Osaka Univ., Japan
Abstract :
The thermoelectric properties of hot-pressed Fe0.91Mn 0.09Si2 (mean diameter:D,=5-10 μm) were measured with changing the powder treatment. In order to improve the thermal conductivity and the electrical conductivity, carbon (0, 1 and 2 wt%, Dm=0.02-0.3 μm) was added and the mechanofusion process was used. The mechanofusion process can produce composite powders with high shear stress and compressive force, allowing a more homogeneous compact to be fabricated. As a result, the thermal conductivity was remarkably improved in this system. EPMA analyses showed that extremely fine particles of carbon were dispersed along grain boundaries without aggregation. However, the electrical conductivity decreased in this case. This is probably because the electrical resistivity of carbon black is very high. However, when graphite are added, the MF process would be very effective to improve the figure of merit, because the process can increase the grain boundary with additives and improves the electrical conductivity
Keywords :
grain boundaries; hot pressing; iron compounds; manganese compounds; powders; thermal conductivity; thermoelectric power; 0.02 to 0.3 mum; 5 to 10 mum; Fe0.91Mn0.09Si2; FeSi2; aggregation; composite powders; compressive force; electrical conductivity; figure of merit; grain boundaries; high shear stress; hot-pressed Fe0.91Mn0.09Si2; mechanofusion process; powder treatment; thermal conductivity; thermoelectric properties; Conducting materials; Electric resistance; Grain boundaries; Mechanical factors; Mortar; Powders; Shafts; Thermal conductivity; Thermal resistance; Thermoelectricity;
Conference_Titel :
Thermoelectrics, 1997. Proceedings ICT '97. XVI International Conference on
Conference_Location :
Dresden
Print_ISBN :
0-7803-4057-4
DOI :
10.1109/ICT.1997.667142
