Crystal Structure and Thermoelectric Properties of YAl ₃ C ₃

Abstract

The crystal structure of YAl 3 C 3 was refined from laboratory X‐ray powder diffraction data (Cu K α 1 ) using the Rietveld method. The crystal structure is hexagonal (space group P 6 3 mc , Z =2) with lattice dimensions a =0.342157(4) nm, c =1.72820(1) nm, and V =0.175217(3) nm 3 . The final reliability indices were R wp =9.94% ( R wp / R e =1.18), R p =7.36%, R B =1.77%, and R F =1.03%. The compound shows an intergrowth structure with electroconductive [YC 2 ] thin slabs separated by Al 4 C 3 ‐type [AlC] layers. This material had thermoelectric properties superior to those of the layered carbides Zr 2 [Al 3.56 Si 0.44 ]C 5 , Zr 2 Al 3 C 4 , and Zr 3 Al 3 C 5 in the temperature range of 500– 1073 K, with a maximal power‐factor value of 1.96 × 10 −4 W·(m·K 2 ) −1 at 1073 K.