【作者】 李伟文；

【导师】 赵新兵；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2002， 硕士

【摘要】 采用快速凝固、悬浮熔炼、粉末冶金等方法制备了β-FeSi₂基热电材料，通过测试电学性能、XRD、SEM等手段，研究了β-FeSi₂基热电材料的电学性能和相变情况，讨论进一步提高β-FeSi₂基合金热电性能的可能性。 对于提高β-FeSi₂基热电材料电学性能的研究表明，Co是较好的n型掺杂剂，而Mn是较好的p型掺杂剂。在各种掺杂配比中，0.67at.％的Co掺杂和2.67at.％的Mn掺杂样品，分别达到各掺杂剂下的最大功率因子，相对于未经掺杂的β-FeSi₂有较大的提高。 对Fe_1-xSm_xSi₂的研究表明，Sm在FeSi₂基热电材料中是以SmSi₂金属相存在，随着Sm量的增加，β-FeSi₂基材料由p型向n型转化，并在含Sm量为13.3at.％时其功率因子达到最大值，为β-FeSi₂的5倍以上。对含Sm的二元金属掺杂研究可以看出，材料的电阻率是由掺入的总原子数决定的。 轻元素（如N、C）的掺杂可以提高β-FeSi₂基热电材料的α值，而对电阻率的影响很小。Ge的掺入，在提高p型β-FeSi₂基热电材料的α值同时还降低了ρ值，是较佳的一种掺杂剂，其功率因子可达β-FeSi₂的10倍以上。 快凝热压法通过细化晶粒使β-FeSi₂基热电材料的电学性能得以大幅度提高，并缩短退火时间。但Sm的存在会使FeSi₂基中生成β相的时间延长。更多还原

【Abstract】 β-FeSi2 based thermoelectric materials were prepared by melt-spinning(MS), levetation-melting(LM) and mechanical alloyiny(MA). Their thermoelectric properties and the mechanism of (3 phase transition were studied by means of the measurements of transport properties, XRD analysis, SEM observations.On the studying of transport properties of p-FeSi2 based alloys, it was observed that cobalt is a effective n-typed dopant while mangnese benefits to the p-typed alloy. It was found that the p-FeSi2 based alloys with 0.67t.% cobalt for n type or 2.67at.% mangnese for p type have the maximum of power factor.The SmSi2 phase was found in Fei.xSmxSi2. With the increasing of x, Fe1-xSmxSi2 converts into n type from p type and Feo.6Smo.4Si2 alloy has the maximum power factor. As for as the alloys with two metal dopants are concerned, the transport properties are controlled by the total atom number while the element Sm plays more important roll in the decreasing of electrical resistivity.The β-FeSi2 based alloys doped with light elements (N, C) or germanium have high Seebeck coefficients and the power factors, for example, the power factor of alloy Feo.9iCro.o9Sii.6Geo.4 is 10 times as high as p-FeSi2Rapidly solidified β-FeSi2 thermoelectric materials have better transport properties and need shorter annealing time because more finer structure was produced by this way. The alloying of Sm in p-FeSi2 alloys slows down the p phase transformation.更多还原