中国物理B ›› 2009, Vol. 18 ›› Issue (1): 287-292.doi: 10.1088/1674-1056/18/1/046

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Quick preparation and thermal transport properties of nanostructured $\beta$-FeSi2 bulk material

李涵, 唐新峰, 曹卫强, 张清杰   

  1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
  • 收稿日期:2008-04-08 修回日期:2008-05-20 出版日期:2009-01-20 发布日期:2009-01-20
  • 基金资助:
    Project supported by the 973 Project (Grant No 2007CB607501), the National Science Foundation of China (Grant No 50572082) and the Cultivation Fund of the Key Scientific and Technical Innovation Project of China (Grant No 705035).

Quick preparation and thermal transport properties of nanostructured β-FeSi2 bulk material

Li Han(李涵), Tang Xin-Feng(唐新峰)†, Cao Wei-Qiang(曹卫强), and Zhang Qing-Jie(张清杰)   

  1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
  • Received:2008-04-08 Revised:2008-05-20 Online:2009-01-20 Published:2009-01-20
  • Supported by:
    Project supported by the 973 Project (Grant No 2007CB607501), the National Science Foundation of China (Grant No 50572082) and the Cultivation Fund of the Key Scientific and Technical Innovation Project of China (Grant No 705035).

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摘要： This paper reports that the nanostructured β-FeSi2 bulk materials are prepared by a new synthesis process by combining melt spinning (MS) and subsequent spark plasma sintering (SPS). It investigates the influence of linear speed of the rolling copper wheel, injection pressure and SPS regime on microstructure and phase composition of the rapidly solidified ribbons after MS and bulk production respectively, and discusses the effects of the microstructure on thermal transport properties. There are two crystalline phases (α-Fe2Si5 and ε-FeSi) in the rapidly solidified ribbons; the crystal grains become smaller when the cooling rate increases (the 20 nm minimum crystal of ε-FeSi is obtained). Having been sintered for 1 min above 1123K and annealed for 5min at 923 K, the single-phase nanostructured β-FeSi2 bulk materials with 200--500nm grain size and 98% relative density are obtained. The microstructure of β-FeSi2 has great effect on thermal transport properties. With decreasing sintering temperature, the grain size decreases, the thermal conductivity of β-FeSi2 is reduced remarkably. The thermal conductivity of β-FeSi2 decreases notably (reduced 72% at room temperature) in comparison with the β-FeSi2 prepared by traditional casting method.

关键词: thermoelectric materials, nanostructure, thermal conductivity

Abstract: This paper reports that the nanostructured $\beta$-FeSi2 bulk materials are prepared by a new synthesis process by combining melt spinning (MS) and subsequent spark plasma sintering (SPS). It investigates the influence of linear speed of the rolling copper wheel, injection pressure and SPS regime on microstructure and phase composition of the rapidly solidified ribbons after MS and bulk production respectively, and discusses the effects of the microstructure on thermal transport properties. There are two crystalline phases ($\alpha$-Fe2Si5 and $\varepsilon$-FeSi) in the rapidly solidified ribbons; the crystal grains become smaller when the cooling rate increases (the 20 nm minimum crystal of $\varepsilon$-FeSi is obtained). Having been sintered for 1 min above 1123K and annealed for 5min at 923 K, the single-phase nanostructured $\beta$-FeSi2 bulk materials with 200--500nm grain size and 98% relative density are obtained. The microstructure of $\beta$-FeSi2 has great effect on thermal transport properties. With decreasing sintering temperature, the grain size decreases, the thermal conductivity of $\beta$-FeSi2 is reduced remarkably. The thermal conductivity of $\beta$-FeSi2 decreases notably (reduced 72% at room temperature) in comparison with the $\beta$-FeSi2 prepared by traditional casting method.

Key words: thermoelectric materials, nanostructure, thermal conductivity

中图分类号:  (Nanocrystalline materials)

  • 81.07.Bc
66.70.-f (Nonelectronic thermal conduction and heat-pulse propagation in solids;thermal waves) 81.16.-c (Methods of micro- and nanofabrication and processing) 81.20.Ev (Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation) 81.30.Fb (Solidification)