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A1: Low temperature materials

Preparation and Thermoelectric Properties of YbAl3 Thermoelectric Materials with Excessive Al

Danqi He, Wenyu Zhao*, Jian Yu, Hongyu Zhou, Wanting Zhu, Qingjie Zhang*
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology

A series of YbAl3 thermoelectric materials with nominal compositions YbAl3+x (x=0~0.3, ∆x=0.1) have been prepared by a melting-quenching-annealing-spark plasma sintering (SPS) method. We explored the effects of the excessive Al on phase compositions, microstructure and transport properties of these materials. The quenched samples are composed of YbAl3, YbAl2, Yb, and Al. All the annealed samples contain a small amount of Al besides main phase YbAl3, but the annealed samples with x<0.2 still contain a small amount of YbAl2. All the SPSed samples are composed of single-phase YbAl3. The electrical conductivity, Seebeck coefficient, power factor, thermal conductivity and ZT values firstly increase at room temperature with increasing the x in the range of 0~0.2 and then decrease when x>0.2. The highest ZT value reaches 0.28 at 300 K for the SPSed sample with x = 0.2.