Lattice Thermal Conductivity Reduction Due to In Situ-Generated Nano-Phase in Bi^sub 0.4^Sb^sub 1.6^Te^sub 3^ Alloys by Microwave-Activated Hot Pressing

• Published in: Journal of electronic materials Vol. 43; no. 11; p. 4327
• Main Authors: Yang, Fan, Fan, Xi An, Rong, Zhen Zhou, Cai, Xin Zhi, Li, Guang Qiang
• Format: Journal Article
• Language: English
• Published: Warrendale Springer Nature B.V 01.11.2014
• Subjects: Alloys; Conductivity; Hot pressing; Lattice theory; Microwave heating; Nanomaterials
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-014-3339-3

The p-type Bi^sub 0.4^Sb^sub 1.6^Te^sub 3^ alloys are prepared using a new method of mechanical alloying followed by microwave-activated hot pressing (MAHP). The effect of sintering temperature on the microstructure and thermoelectric properties of Bi^sub 0.4^Sb^sub 1.6^Te^sub 3^ alloys is investigated. Compared with other sintering techniques, the MAHP process can be used to produce relatively compact bulk materials at lower sintering temperatures owing to its unique sintering mechanism. The grain size of the MAHP specimens increases gradually with the sintering temperature and a partially oriented lamellar structure can be formed in some regions of specimens obtained. The formation of the in situ-generated nano-phase is induced by the arcing effect of the MAHP process, which enhances the phonon scattering effect and decreases the lattice thermal conductivity. A minimum lattice thermal conductivity of 0.41 W/(m·K) and a maximum figure of merit value of 1.04 are obtained at 100°C for the MAHP specimen sintered at 325°C. This technique may also be extended to other functional materials to obtain ultrafine microstructures at low sintering temperatures.[PUBLICATION ABSTRACT]