β-phase transformation and thermoelectric power in FeSi2 and Fe2Si5 based alloys containing small amounts of Cu
β-phase transformation and thermoelectric power in FeSi2 and Fe2Si5 based alloys containing small amounts of Cu
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DOI：
10.1016/s0925-8388(97)00165-5
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发表时间：
1997-09
影响因子：
6.2
通讯作者：
I. Yamauchi;T. Okamoto;Hajime Ohata;I. Ohnaka
中科院分区：
文献类型：
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作者：
I. Yamauchi;T. Okamoto;Hajime Ohata;I. Ohnaka
研究了在不同的FeSi2和Fe2Si5基合金中添加铜对β相形成速率和温差电势的影响。在FeSi2合金中，铜的加入使包晶反应(a+ε→β)开始增强，但随退火时间延长而变慢。残留的金属ϵ对热电功率是有害的。(FeSi2)99−XMn1CuX(X=0-1.0at.%)，(FeSi2)99−XCo1CuX(X=0-1.0at.%)合金在去除ϵ后获得了固有的热电性能。在共析反应(α→β+Si)的情况下。差热分析、X射线衍射和显微观察清楚地证实了少量铜的加入显著地提高了共析反应速率，并且随着铜含量的降低，共析反应速率降低。这一速率还与退火温度有关，大多数合金在1073K左右达到最大值。即使在锰或钴掺杂的合金中，仅添加0.1at.%的铜仍然是非常有效的。这些合金的温差电势随退火时间的延长而迅速增大。它们的终值随着铜含量的增加而减小，并在0.2at.%的铜含量下饱和。添加0.1at.%Cu的合金比传统的p型和a型FeSi2基合金的值都要高。这些结果表明，含少量铜的Fe2Si5合金可能是一种很有吸引力的新型热电材料。
The effects of Cu addition on the β phase formation rate and the thermoelectric power in various FeSi2and Fe2Si5based alloys was examined. The peritectoid reaction (a+ε→β) in FeSi2alloys was initially enhanced by the addition of Cu but it became slower for longer annealing times. The retained metallic ϵ was harmful for the thermoelectric power. The inherent thermoelectric properties of (FeSi2)99−XMn1CuX(X=0–1.O at.%), (FeSi2)99−XCo1CuX(X=0–1.0 at.%) alloys were attained after the elimination of ϵ. In the case of eutectoid reaction (α→β+Si). Differential thermal analysis, X-ray diffraction and microscopic observation clearly confirmed that the eutectoid reaction rate was drastically enhanced by the addition of a small amount of Cu and its rate decreased with decreasing Cu content. The rate also depends on the annealing temperature and reached a maximum at about 1073 K for most alloys. The addition of only 0.1 at.% Cu was still very effective even in Mn or Co doped alloys. The thermoelectric power of these alloys increased very quickly with annealing time. Their final values decreased with Cu content and saturated at 0.2 at.% Cu. The value of the 0.1 at.% Cu added alloy was higher than that of both the conventional p- and a-type FeSi2based alloys. These results suggest that the Fe2Si5alloys with a small amount of Cu may be attractive as new thermoelectric materials.