摘要
采用快速凝固方法制备了FeSi2基热电材料Fe0.92Mn0.08Six(x=1.9、2.0、2.1、2.3、2.5)粉末,在高真空下采用热压法制备了块状热电材料。X射线衍射分析表明,所有试样热压后均达到了相平衡,而且x=1.9和2.0的试样热压后就完成了β FeSi2相转变,随着Si含量的增加,β相逐渐减少,α相逐渐增多。热压试样经800℃退火20h后,完全转变为β半导体相。热压退火试样的致密度为93%～98%。研究发现,弥散分布的过量Si较少时,有利于提高β FeSi2基热电材料的性能。名义成份为Fe0.92Mn0.08Si2.1的试样在高温区的无量纲优值最大,650℃时达到0.18。但是,当Si过量较多时,试样的热导率明显增加,显著降低了试样的优值。
Fe_(0.92)Mn_(0.08)Si__x_(_x_=1.9, 2.0, 2.1, 2.3, 2.5) thermoelectric alloys have been prepared by rapid solidification and hot uniaxial pressing (HUP) with 50 MPa for 30min at 975℃. XRD analyses showed that all samples reached to phase equilibrium after HUP and the α-Fe_2Si_5 transformed completely to β-FeSi_2 phase after 800℃ annealing for 20h. 93%～98% of the theoretical densities have been obtained by the annealed samples. It was found that a small amount of dispersed fine silicon particles were of benefit to the improvement of the thermoelectric figure of merit of β-FeSi_2 based alloys. The highest figure of merit, 0.18, has been obtained for the sample Fe_(0.92)Mn_(0.08)Si_(2.1) at 650℃. However, when more excessive silicon added, the thermoelectric figures of merit decrease due to higher thermal conductivities.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2003年第6期693-695,共3页
Journal of Functional Materials
基金
国家自然科学基金资助项目(59971044
50171064)
