Preparation of rare-earth element doped Mg_2Si by FAPAS  

作　　者：王丽七 孟庆森 樊文浩 

机构地区：[1]Department of Mechanical Engineering,Anhui Vocational College of Defense Technology [2]Department of Material Science and Engineering,Taiyuan University of Technology

出　　处：《Journal of Semiconductors》2012年第11期32-36,共5页半导体学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.50671070,50975190);the SXSCC(No.200826)

摘　　要：Rare-earth elements（Re） Sc and Y doped Mg_2Si thermoelectric materials were made via a field-activated and pressure-assisted synthesis（FAPAS） method at 1023-1073 K,50 MPa for 15 min.The samples created using this method have uniform and compact structures.The average grain size was about 1.5-2μm,the micro-content of Re did not change the matrix morphology.The sample with 2500 ppm Sc obtained the best Seebeck coefficient absolute value,about 1.93 times of that belonging to non-doped Mg_2Si at about 408 K.The electric conductivity of the sample doped with 2000 ppm Y becomes 1.69 times of that of pure Mg_2Si at 468 K,while the former had a better comprehensive electrical performance.Their thermal conductivity was reduced to 70%and 84% of that of non-doped Mg_2Si.Thus,the figure of merit and ZT of these two samples were enhanced visibly,which were 3.3 and 2.4 times of the non-doped samples at 408 K and 468 K,respectively.The maximal ZT belonging to samples doped with 2500 ppm Sc went up to 0.42 at about 498 K,higher than 0.40 of sample doped with 2000 ppm Y at 528 K and 0.25 of non-doped Mg_2Si at 678 K,and the samples doped with Sc seemed to get the best thermoelectric performances at lower temperature.Rare-earth elements（Re） Sc and Y doped Mg_2Si thermoelectric materials were made via a field-activated and pressure-assisted synthesis（FAPAS） method at 1023-1073 K,50 MPa for 15 min.The samples created using this method have uniform and compact structures.The average grain size was about 1.5-2μm,the micro-content of Re did not change the matrix morphology.The sample with 2500 ppm Sc obtained the best Seebeck coefficient absolute value,about 1.93 times of that belonging to non-doped Mg_2Si at about 408 K.The electric conductivity of the sample doped with 2000 ppm Y becomes 1.69 times of that of pure Mg_2Si at 468 K,while the former had a better comprehensive electrical performance.Their thermal conductivity was reduced to 70%and 84% of that of non-doped Mg_2Si.Thus,the figure of merit and ZT of these two samples were enhanced visibly,which were 3.3 and 2.4 times of the non-doped samples at 408 K and 468 K,respectively.The maximal ZT belonging to samples doped with 2500 ppm Sc went up to 0.42 at about 498 K,higher than 0.40 of sample doped with 2000 ppm Y at 528 K and 0.25 of non-doped Mg_2Si at 678 K,and the samples doped with Sc seemed to get the best thermoelectric performances at lower temperature.

关 键 词：Mg_2Si rare-earth element thermoelectric material FAPAS 

分 类 号：TB34[一般工业技术—材料科学与工程]