日本金属学会誌

J. Japan Inst. Met. Mater, Vol. 79, No. 11 (2015),
pp. 586-590

Thermal Conductivity of β-FeSi2–Si Self-Assembled Nanocomposite

Yuji Ohishi1, Shingo Okajima1, Yoshinobu Miyazaki1, Hiroaki Muta1, Ken Kurosaki1 and Shinsuke Yamanaka1,2

1Graduate School of Engineering, Osaka University, Suita 565-0871
2Research Institute of Nuclear Engineering, University of Fukui, Turuga 914-0055

Abstract:

In the present study, we synthesized composite material composed of Si and β-FeSi2 by self-assembly process. In this process, mesoscale α-FeSi2 and Si crystals were formed by rapidly solidifying Fe-Si alloys with eutectic composition (Fe:Si=26:74) using melt spinning. Nanoscale β-FeSi2 and Si crystals were formed by subsequent heat treatment by eutectoid decomposition from α-FeSi2 to β-FeSi2 and Si. Scanning electron microscope observation showed that two kinds of Si precipitates were formed in the β-FeSi2 matrix: Si particle with a diameter of 100–200 nm and Si nanoscale lamellar plates with a thickness of about 50 nm. The thermal conductivity of the composite was significantly reduced compared to the effective thermal conductivity of Si and β-FeSi2 composite calculated based on effective medium approximation. This result indicates that the thermal conductivity was reduced by enhanced phonon scattering by the formed nanostructure.

[doi:10.2320/jinstmet.JA201509]


(Received 2015/4/30)

Keywords:

thermal conductivity, eutectic reaction, eutectoid decomposition


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