Thermoelectric Properties of Bi0.5Sb1.5Te3 Prepared by the Ultrarapid Quenching Process

P-type Bi0.5Sb1.5Te3 thermoelectric materials have been prepared by ultrarapid quenching method with various cooling rates. The microstructures of sample are very different from those prepared by normal cooling. The ultrarapid quenched material was obtained in the shape of foils, the thickness of which were found to vary in the range of 6-20 μm, which corresponds to a cooling rate of about 106 K/S. X-ray diffraction evidenced a microcrystalline structure of the expected composition with a (0015) plane. Increasing the cooling rate, the Seebeck coefficient increase, the electrical conductivity decrease and the power factor rise up to 4.4×10-3 Wm-1K-2 .The highest ZT value of 1.22 was achivedachieved for the materials with the copper roller roration speed 40 m/s in room temperarure.

Microstructure and Thermoelectric Properties of Thin Foils of Bismuth Telluride Alloys

Ultrarapid quenching processes have been extensively studied during the past few years. particularly for glasses. In the case of polycrystalline materials, the problem is slightly different. In this case, the microstructures obtained by this process are very different from those obtained by normal cooling and they induce new physical properties.