[SIS8] Sintered Materials

[14F-SIS8-01] Special Invited: Densification of Thermoelectric β-FeSi₂ by Directly Applied Current Sintering Process

*M. Ito¹ (1.Fukui University of Technology, Japan)

Keywords:thermoelectric materials, directly applied current sintering, densification, fine microstructure

The thermoelectric β-FeSi₂ powder was sintered by modified pulsed electric current sintering (PECS) using graphite punches and an insulating quartz glass die. The sample powders were heated by directly applied current and their sintering behaviors were compared to those of the samples sintered by the conventional PECS (using graphite punches and a graphite die). During the heating in the quartz die, the transformation from mechanically alloyed metallic Fe-Si powder to the semiconductive β-FeSi₂ phase occurred at a temperature lower than when sintered by the conventional PECS. After the transformation, the shrinkage of compact became larger than that of the sample sintered by the conventional method. The sample sintered by this modified PECS process showed the thermal conductivity smaller than the sample prepared in the conventional process because of its finer microstructure due to the rapid densification, resulting in lager figure of merit.