Thermoelectric properties and microstructure of Ba 8Al 14Si 31 and EuBa 7Al 13Si 33

Cathie L. Condron, Susan M. Kauzlarich, Franck Gascoin, G. Jeffery Snyder

Research output: Contribution to journalArticle

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Abstract

Powder samples of the type I clathrate phases, with the proposed stoichiometry Ba 8Al 16Si 30 and Eu 2Ba 6Al 16Si 30, were synthesized using direct reaction of stoichiometric amounts of the elements. Rietveld refinement of powder X-ray diffraction data is consistent with the clathrate type I structure. Composition, microstructure, and thermoelectric property measurements were made on hot-pressed pellets. Stoichiometry of the Ba 8Al 16Si 30 sample was determined from microprobe data to be Ba 8Al 14Si 31, close to the deficient framework solid solution of the general formula, Ba 8Al xSi 42-3/4x[] 4-1/4x (x -14; [], open square indicates lattice defect). In the case of the rare-earth-substituted compound, microprobe analysis of the microstructure indicates that it is not single phase, but contains multiple components, most of the general clathrate stoichiometry. The majority phase has the stoichiometry EuBa 7Al 13Si 32. Both phases show conductivity typical of heavily doped semiconductors with negative Seebeck coefficients. The highest Seebeck coefficients are - 99 and -71 μV/K at 1192 K for Ba 8Al 14Si 31 and EuBa 7Al 13Si 33, respectively. The maximum zT is 0.34 at 1150 K and 0.22 at 1165 K for Ba 8Al 14Si 31 and EuBa 7Al 13Si 33, respectively.

Original languageEnglish (US)
Pages (from-to)4939-4945
Number of pages7
JournalChemistry of Materials
Volume18
Issue number20
DOIs
StatePublished - Oct 3 2006

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Stoichiometry
Microstructure
Seebeck coefficient
Rare earth compounds
Rietveld refinement
Crystal defects
Powders
X ray powder diffraction
Solid solutions
Semiconductor materials
Chemical analysis

ASJC Scopus subject areas

  • Materials Chemistry
  • Materials Science(all)

Cite this

Condron, C. L., Kauzlarich, S. M., Gascoin, F., & Snyder, G. J. (2006). Thermoelectric properties and microstructure of Ba 8Al 14Si 31 and EuBa 7Al 13Si 33 Chemistry of Materials, 18(20), 4939-4945. https://doi.org/10.1021/cm061483u

Thermoelectric properties and microstructure of Ba 8Al 14Si 31 and EuBa 7Al 13Si 33 . / Condron, Cathie L.; Kauzlarich, Susan M.; Gascoin, Franck; Snyder, G. Jeffery.

In: Chemistry of Materials, Vol. 18, No. 20, 03.10.2006, p. 4939-4945.

Research output: Contribution to journalArticle

Condron, CL, Kauzlarich, SM, Gascoin, F & Snyder, GJ 2006, 'Thermoelectric properties and microstructure of Ba 8Al 14Si 31 and EuBa 7Al 13Si 33 ', Chemistry of Materials, vol. 18, no. 20, pp. 4939-4945. https://doi.org/10.1021/cm061483u
Condron, Cathie L. ; Kauzlarich, Susan M. ; Gascoin, Franck ; Snyder, G. Jeffery. / Thermoelectric properties and microstructure of Ba 8Al 14Si 31 and EuBa 7Al 13Si 33 In: Chemistry of Materials. 2006 ; Vol. 18, No. 20. pp. 4939-4945.
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