机械合金化法制备Co掺杂β-FeSi_2及性能分析  

Property analysis of Co-doped β-FeSi_2 thermoelectric materials processed by mechanical alloying

作　　者：王东静[1,2] 李凡[1,2] 黄海波[1,2] 

机构地区：[1]东南大学材料科学与工程学院,南京211189 [2]东南大学江苏省先进金属材料高技术研究重点实验室,南京211189

出　　处：《东南大学学报（自然科学版）》2009年第5期1033-1037,共5页Journal of Southeast University：Natural Science Edition

基　　金：国家重点基础研究发展计划(973计划)资助项目(2007CB616903)

摘　　要：用机械合金化法成功制备了配比为Fe1-xCoxSi2(x=0.04,0.05,0.06)的N型β-FeSi2基热电材料.研究结果表明:在球料质量比为80:1,球磨速度为400r/min的条件下,球磨20h的粉体发生完全合金化,生成β-FeSi2,α-Fe2Si5和ε-FeSi的合金相;经过1373K退火2h,再结合1073K退火2h的热处理后,可完全获得晶粒细小的N型块状β-FeSi2;随着测量温度的升高,Fe1-xCoxSi2试样的Seebeck系数α和电导率σ增大,热导率κ降低,无量纲热电优值ZT随温度升高而明显增大;随着掺杂量的增加,材料的电导率σ增大,热导率κ降低,σ/κ比值得到提高,但Seebeck系数α降低;当T=695K,掺杂量x=0.04时,Seebeck系数α的最大绝对值为227μV/K;具有最佳热电优值的材料为Fe0.95Co0.05Si2.Co-doped N-type β-FeSi2 thermoelectric materials Fe1-xCoxSi2 （ X = 0. 04,0. 05,0. 06 ） are successfully prepared by mechanical alloying method. It is indicated that under the condition of balls to powders mass ratio of 80： 1, rotation speed of 400 r/min and milling time of 20 h, powders are composed of β-FeSi2, α-Fe2Si5 and ε-FeSi interrnetallic compound. And, a single-phase Co-doped N-type β-FeSi2 bulks with refined grain can be obtained after annealing at 1 373 K for 2 h and 1 073 K for 2 h. With the increase of measuring temperature, Seebeck coefficient a, electric conductivity σ and thermoelectric figure of merit ZT increase directly while thermal conductivity κ decreases inversely; with the increase of Co addition, σ ascends while κ and a of Fe1-xCoxSi2 alloy reduce, leading to a growth of the ratio σ/κ. When the temperature reaches 695 K and the amount of Co-addition x gets 0. 04, Seebeck coefficient shows the maximum absolute value of 227 μV/K. The maximum figure of merit is obtained in Fe0 95 Co0.05 Si2.

关 键 词：β-FeSi2热电材料 机械合金化 掺杂 热电性能 

分 类 号：TB34[一般工业技术—材料科学与工程] TF124[冶金工程—粉末冶金]