Seebeck coefficient and electrical resistivity of some rare earth ternary sulfides La/sub 3-x/M/sub x/S/sub 4/ (M = Sm, Eu, Yb)

Conference · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5827615

Nakahara, J F; Tschetter, M J; Beaudry, B J; Takeshita, T; Gschneidner, Jr, K A

Binary lanthanum sulfides with compositions between La/sub 2/S/sub 3/ and La/sub 3/S/sub 4/ form a continuous series of solid solutions in the high temperature gamma form and have been reported to have high figures of merit. In this study, in order to achieve increased stability of the gamma form, compounds with the formula La/sub 3-x/M/sub x/S/sub 4/ (M = Sm, Eu, Tb and x = 0.1 to 0.9) were prepared. The Seebeck coefficients and electrical resistivities of these ternary sulfides are reported as well as some preliminary results on their long term thermal stability. The compounds La/sub 3-x/M/sub x/S/sub 4/ (M = Sm, Eu, Yb and x = 0.1 to 0.9) prepared in this study all possessed the high temperature ..gamma..-Th/sub 3/P/sub 4/ structure and the compounds with small values of x possessed attractive thermoelectric properties. The figure of merit at 1000/sup 0/C of these compounds is in the neighborhood of 0.7 to 0.8 x 10/sup -3/ /sup 0/C/sup -1/ when the thermal conductivity is taken to be 15 mW/sup 0/C/sup -1/cm/sup -1/ and is comparable to that of binary LaS/sub x/ and SiGe alloys. Long term vaporiation data indicate that these materials are stable in vacuum for an extended period of time. 12 refs., 4 figs., 1 tab.

• Research Organization: Ames Lab., IA (USA); Mitsubishi Metal Corp., Omiya, Saitama (Japan). Central Research Lab.; Iowa State Univ. of Science and Technology, Ames (USA). Dept. of Materials Science and Engineering
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5827615
• Report Number(s): IS-M-580; CONF-860301-1; ON: DE86011401
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300303* -- Thermoelectric Generators-- Materials
Components
& Auxiliaries
BINARY MIXTURES
CHALCOGENIDES
DATA
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EUROPIUM COMPOUNDS
EUROPIUM SULFIDES
EVAPORATION
EXPERIMENTAL DATA
INFORMATION
LANTHANUM COMPOUNDS
LANTHANUM SULFIDES
MATERIALS
MIXTURES
NUMERICAL DATA
PHASE STABILITY
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SAMARIUM COMPOUNDS
SAMARIUM SULFIDES
SEEBECK EFFECT
SOLID SOLUTIONS
SOLUTIONS
STABILITY
SULFIDES
SULFUR COMPOUNDS
TEMPERATURE DEPENDENCE
THERMOELECTRIC MATERIALS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM SULFIDES