Synthesis and thermoelectric properties of double-atom-filled skutterudite compounds Ca{sub m}Ce{sub n}Fe{sub x}Co{sub 4-x}Sb{sub 12}

Journal Article · Fri Dec 15 00:00:00 EST 2006 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2375017· OSTI ID:20884942

Xinfeng, Tang; Han, Li; Qingjie, Zhang; Niino, Masayuki; Goto, Takashi ^[1]

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1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

Single-phase Ca{sub m}Ce{sub n}Fe{sub x}Co{sub 4-x}Sb{sub 12} compounds filled by Ca and Ce were synthesized by using melting-quench-diffusion annealing reaction method. The structure and thermoelectric properties of double atoms filled skutterudite compounds were investigated. The results of Rietveld refinement indicate high reliabilities of filling fractions consistent with the inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis, Ca{sub m}Ce{sub n}Fe{sub x}Co{sub 4-x}Sb{sub 12} compounds possess skutterudite structure, and Sb-icosahedron voids were filled with Ca or Ce. The thermal parameter B{sub Ca/Ce} (6.0) of Ca/Ce is much larger than that of B{sub Sb} (0.3) and B{sub Fe/Co} (0.3) of Sb and Fe/Co. The specific chemical states of atoms were obtained from x-ray photoelectron spectroscopy quantitative analysis, which shows that Sb has five chemical states and the relative content is correlative with the total filling fraction; the filling atoms have three filling positions and tend to fill the center position of the Sb-icosahedron voids, preferentially. With the same filling fraction, carrier concentration and electrical conductivity of p-type Ca{sub m}Ce{sub n}Fe{sub x}Co{sub 4-x}Sb{sub 12} are intervenient between that of single atom filled compounds Ca{sub m}Fe{sub x}Co{sub 4-x}Sb{sub 12} and Ce{sub n}Fe{sub x}Co{sub 4-x}Sb{sub 12}, and decreased with increasing Ca and Ce, especially Ce, filling fraction. The Seebeck coefficients are increased with increasing total filling fraction, and the influence of Ce filling fraction to the Seebeck coefficients is more notable than that of Ca, and with the same filling fraction, the lattice thermal conductivity of Ca{sub m}Ce{sub n}Fe{sub x}Co{sub 4-x}Sb{sub 12} is smaller than that of Ca{sub m}Fe{sub x}Co{sub 4-x}Sb{sub 12} and Ce{sub n}Fe{sub x}Co{sub 4-x}Sb{sub 12}; furthermore, when the total filling fraction (m+n) is about 0.3 and the respective filling fraction of Ca and Ce is approximately identical, the lattice thermal conductivity reached the minimum value. The greatest ZT value of 1.2 was obtained at 750 K for p-type Ca{sub 0.18}Ce{sub 0.12}Fe{sub 1.45}Co{sub 2.55}Sb{sub 12} compound.

• OSTI ID: 20884942
• Journal Information: Journal of Applied Physics, Vol. 100, Issue 12; Other Information: DOI: 10.1063/1.2375017; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
ANTIMONY ALLOYS
AUGER ELECTRON SPECTROSCOPY
CALCIUM ALLOYS
CARRIER DENSITY
CERIUM ALLOYS
CHEMICAL STATE
COBALT ALLOYS
ELECTRIC CONDUCTIVITY
EMISSION SPECTROSCOPY
IRON ALLOYS
PLASMA
QUENCHING
SEEBECK EFFECT
SYNTHESIS
THERMAL CONDUCTIVITY
THERMOELECTRIC PROPERTIES
X-RAY PHOTOELECTRON SPECTROSCOPY