Thermoelectric Properties of Bulk Yttrium Silicide (YSi2) Fabricated by Arc Melting and Spark Plasma Sintering

Abstract

Yttrium silicide (YSi 2 ) nanoparticles in SiGe are reported to enhance the thermoelectric figure-of-merit (ZT) to the recorded value (%1.81). However, the thermoelectric properties of bulk YSi 2 has never been reported. In this work, the thermoelectric properties of YSi 2 is studied for the first time. The bulk YSi 2 is fabricated by arc melting highly pure Si and Y raw materials. The ingot is crushed to powder and compacted to form a highly dense pellet by spark plasma sintering. By optimizing the processing parameters, the single phase with the AlB 2 -type structure (P6/mmm) is formed. The Hall measurements show that YSi 2 exhibit a metallic-like behavior with a very high electron concentration. This result in the thermoelectric properties with a very large electrical conductivity (%18 Â 10 5 Ω À1 m À1 ) but a small Seebeck coefficient (À26 mV K À1 ) at room temperature, and decrease with temperature. The thermal conductivity is around 14-19 W m À1 K À1 for all temperature range. The maximum ZT value is 0.026 at 423 K.