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采用燃烧合成-热处理工艺制备热电材料β-FeSi2,研究了Cu掺杂和不同的硅含量对β-FeSi2相变的影响。利用X射线衍射仪和扫描电子显微镜分析了合成的铁硅间化合物的相组成及其微观形貌。结果表明:掺杂0.5 at%的Cu在热处理过程中能提高共析反应(α→β+Si)的反应进程,完全地将α-Fe2Si5转变为β-FeSi2,形成P型半导体。在混料阶段按Fe∶Si=1∶3的原子比例制备β-FeSi2,XRD分析表明,过量的Si单质提高了Si+ε→β的相转变过程,很大程度上能够消除ε相,增加β-FeSi2的含量。
The thermoelectric material β-FeSi2 was prepared by a combustion synthesis-heat treatment process. The effects of Cu doping and different silicon contents on the β-FeSi2 phase transition were investigated. The phase composition and microstructure of the synthesized Fe-Si compounds were analyzed by X-ray diffraction and scanning electron microscopy. The results show that the Cu doped with 0.5 at% can improve the reaction process of the eutectoid reaction (α → β + Si) during the heat treatment and completely transform the α-Fe2Si5 into β-FeSi2 to form a P-type semiconductor. The β-FeSi2 is prepared by the atomic ratio of Fe: Si = 1: 3 during the mixing stage. The XRD results show that the excess Si increases the phase transformation of Si + ε → β, largely eliminating the ε phase and increasing β-FeSi2 content.