Synthesis, crystal structure and thermoelectric properties of a new carbide Zr2[Al3.56Si0.44]C5

✍ Scribed by Koichiro Fukuda; Miyuki Hisamura; Tomoyuki Iwata; Nobuyuki Tera; Kimiyasu Sato

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 829 KB
• Volume: 180
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2007.04.004

✦ Synopsis

A new quaternary layered carbide, Zr 2 [Al 3.56 Si 0.44 ]C 5 , has been synthesized and characterized by X-ray powder diffraction, transmission electron microscopy and thermopower and electrical conductivity measurements. The crystal structure was successfully determined using direct methods, and further refined by the Rietveld method. The crystal is trigonal (space group R3m, Z ¼ 3) with lattice dimensions of a ¼ 0.331059(5), c ¼ 4.09450(5) nm and V ¼ 0.38864(1) nm 3 . The final reliability indices calculated from the Rietveld refinement were R wp ¼ 6.24%, R p ¼ 4.21% and R B ¼ 0.82%. The crystal structure is composed of electroconductive NaCl-type ZrC slabs separated by Al 4 C 3 -type [Al 3.56 Si 0.44 ]C 3 layers. This material had thermoelectric properties superior to those of the ternary layered carbides Zr 2 Al 3 C 4 and Zr 3 Al 3 C 5 , with the power factor reaching 7.6 Â 10 À5 W m À1 K À2 .