Effect of Ti Substitution on Thermoelectric Properties of W-Doped Heusler Fe^sub 2^VAl Alloy

• Published in: Journal of electronic materials Vol. 42; no. 7; p. 1801
• Main Authors: Mikami, M, Ozaki, K, Takazawa, H, Yamamoto, A, Terazawa, Y, Takeuchi, T
• Format: Journal Article
• Language: English
• Published: Warrendale Springer Nature B.V 01.07.2013
• Subjects: Alloys; Electric properties; Electricity generation; Powder metallurgy; Semiconductor doping; Japan
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-012-2433-7

Issue Title: 2012 International Conference on Thermoelectrics. Guest Editors: Ryoji Funahashi, Donald Morelli, Lasse Rosendahl, and Jihui Yang Effects of element substitutions on thermoelectric properties of Heusler Fe^sub 2^VAl alloys were evaluated. By W substitution at the V site, the thermal conductivity is reduced effectively because of the enhancement of phonon scattering resulting from the introduction of W atoms, which have much greater atomic mass and volume than the constituent elements of Fe^sub 2^VAl alloy. W substitution is also effective to obtain a large negative Seebeck coefficient and high electrical conductivity through an electron injection effect. To change the conduction type from n-type to p-type, additional Ti substitution at the V site, which reduces the valence electron density, was examined. A positive Seebeck coefficient as high as that of conventional p-type Fe^sub 2^VAl alloy was obtained using a sufficient amount of Ti substitution. Electrical resistivity was reduced by the hole doping effect of the Ti substitution while maintaining low thermal conductivity. Compared with the conventional solo-Ti-substituted p-type Fe^sub 2^VAl alloy, the ZT value was improved, reaching 0.13 at 450 K.[PUBLICATION ABSTRACT]