Enhanced thermoelectric properties of NbCoSn half-Heuslers through in-situ nanocrystallization of amorphous precursors during the consolidation process  

作　　者：Chanwon Jung Kyuseon Jang Hail Park Jeongin Jang Hanhwi Jang Byungchul Kang Kitae Park Siyuan Zhang Ruben Bueno Villoro SuDong Park Ho Jin Ryu Yeon Sik Jung Min-Wook Oh Christina Scheu Seong-Hoon Yi Pyuck-Pa Choi 

机构地区：[1]Department of Materials Science and Engineering,Korea Advanced Institute of Science and Technology(KAIST),291 Daehak-ro,Yuseong-gu,Daejeon 34141,Republic of Korea [2]Max-Planck-Institut für Eisenforschung GmbH,Düsseldorf 40237,Germany [3]Electrical Materials Research Division,Energy Conversion Research Center,Korea Electrotechnology Research Institute(KERI),Changwon 51543,Republic of Korea [4]Department of Materials Science and Metallurgical Engineering,Kyungpook National University,80 Daehakro,Daegu 41566,Republic of Korea [5]Department of Nuclear and Quantum Engineering,Korea Advanced Institute of Science and Technology(KAIST),291 Daehak-ro,Yuseong-gu,Daejeon 34141,Republic of Korea [6]Department of Materials Science and Engineering,Hanbat National University,125 Dongseodae-ro,Yuseong-gu,Daejeon 34158,Republic of Korea

出　　处：《Journal of Materials Science & Technology》2023年第34期39-48,共10页材料科学技术（英文版）

基　　金：the Basic Science Research Program of the National Research Foundation of Korea(NRF)(Nos.2021R1A4A2001658 and 2021R1A6A3A03045488).

摘　　要：Tailoring nanostructures is a general approach used to obtain enhanced thermoelectric properties for halfHeusler compounds because the wide areas of grain and phase boundaries could be scattering centers that lower lattice thermal conductivity.However,a common fabrication method based on the sintering of crystalline precursors crushed from as-cast alloy ingots has limitations in obtaining a homogeneous microstructure without microsized impurity phases,owing to residual elemental segregation from casting.In this study,we used amorphous NbCoSn alloys as a precursor for the sintered specimen to obtain a homogeneous NbCoSn bulk specimen without microsized impurity phases and segregation,which led to the enhanced Seebeck coefficient due to the high purity of the half-Heusler phase after crystallization.Moreover,superplasticity originating from amorphous features enabled the powders to be largely deformed during the sintering process,even at a low sintering temperature(953 K).This resulted in less oxidation at both,the grain boundary and the interior,as the O diffusion pathway was blocked during the sintering process.As a result,the NbCoSn0.95Sb0.05 specimen using an amorphous precursor exhibited an enhanced zT of 0.7,due to the increase in the power factor and a decrease in lattice thermal conductivity compared to the specimen using a crystalline precursor.

关 键 词：Half-Heusler compounds AMORPHOUS SUPERPLASTICITY SEGREGATION Atom probe tomography 

分 类 号：TB34[一般工业技术—材料科学与工程]