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采用燃烧合成-热压工艺制备热电材料β-FeSi2,研究了热压温度和热压压力对铁硅间化合物相变的规律。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结构形貌。结果表明:当铁硅原子比Fe∶Si为1∶3,添加0.50 at%的Cu时,燃烧合成的产物主要为α-Fe2Si5和Si。热压温度为760℃时α-Fe2Si5完全转变为β-FeSi2,且压力的升高有助于β-FeSi2生成和产物致密度的提高。α-Fe2Si5分解发生共析反应时,部分Si固溶于β-FeSi2内形成了β-FeSi2合金。另一部分Si微粒粘附于β-FeSi2颗粒上,Si在β相的弥散分布可提高热电优值。
The β-FeSi2 thermoelectric material was prepared by combustion synthesis-hot pressing process. The phase transformation between the Fe-Si compounds by hot pressing and hot pressing was studied. The phase composition and microstructure of the synthesized Fe-Si compounds were characterized by X-ray diffraction and scanning electron microscopy. The results show that the products of combustion synthesis are mainly α-Fe2Si5 and Si when the iron-silicon atomic ratio of Fe: Si is 1: 3 and 0.50 at% Cu is added. When the hot pressing temperature is 760 ℃, α-Fe2Si5 completely changes to β-FeSi2, and the increase of pressure contributes to the formation of β-FeSi2 and the increase of product density. When α-Fe2Si5 decomposes and eutectoid reaction occurs, part of Si is dissolved in β-FeSi2 to form β-FeSi2 alloy. Another part of the Si particles adhering to the β-FeSi2 particles, Si in the β phase dispersion distribution can improve the thermoelectric excellent value.