Effects of Rh on the thermoelectric performance of the p-type Zr{sub 0.5}Hf{sub 0.5}Co{sub 1-x}Rh{sub x}Sb{sub 0.99}Sn{sub 0.01} half-Heusler alloys

Journal Article · Sat May 15 00:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.03.023· OSTI ID:21372600

Maji, Pramathesh ^[1]; Takas, Nathan J; Misra, Dinesh K ^[1]; Gabrisch, Heike ^[1]; Stokes, Kevin ^[1]

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1. Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States)

We show that Rh substitution at the Co site in Zr{sub 0.5}Hf{sub 0.5}Co{sub 1-x}Rh{sub x}Sb{sub 0.99}Sn{sub 0.01} (0<=x<=1) half-Heusler alloys strongly reduces the thermal conductivity with a simultaneous, significant improvement of the power factor of the materials. Thermoelectric properties of hot-pressed pellets of several compositions with various Rh concentrations were investigated in the temperature range from 300 to 775 K. The Rh 'free' composition shows n-type conduction, while Rh substitution at the Co site drives the system to p-type semiconducting behavior. The lattice thermal conductivity of Zr{sub 0.5}Hf{sub 0.5}Co{sub 1-x}Rh{sub x}Sb{sub 0.99}Sn{sub 0.01} alloys rapidly decreased with increasing Rh concentration and lattice thermal conductivity as low as 3.7 W/m*K was obtained at 300 K for Zr{sub 0.5}Hf{sub 0.5}RhSb{sub 0.99}Sn{sub 0.01}. The drastic reduction of the lattice thermal conductivity is attributed to mass fluctuation induced by the Rh substitution at the Co site, as well as enhanced phonon scattering at grain boundaries due to the small grain size of the synthesized materials. - Graphical abstract: Significant reduction of the lattice thermal conductivity with increasing Rh concentration in the p-type Zr{sub 0.5}Hf{sub 0.5}Co{sub 1-x}Rh{sub x}Sb{sub 0.99}Sn{sub 0.01} half-Heusler materials prepared by solid state reaction at 1173 K.

• OSTI ID: 21372600
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 5; Other Information: DOI: 10.1016/j.jssc.2010.03.023; PII: S0022-4596(10)00113-1; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIMONY ALLOYS
COBALT ALLOYS
GRAIN BOUNDARIES
GRAIN SIZE
HAFNIUM ALLOYS
HEUSLER ALLOYS
PERFORMANCE
RHODIUM ALLOYS
SCATTERING
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
THERMAL CONDUCTIVITY
THERMOELECTRIC MATERIALS
THERMOELECTRIC PROPERTIES
TIN ALLOYS
ZIRCONIUM ALLOYS
ALLOYS
ALUMINIUM ALLOYS
COPPER ALLOYS
COPPER BASE ALLOYS
CORROSION RESISTANT ALLOYS
ELECTRICAL PROPERTIES
MANGANESE ALLOYS
MATERIALS
MICROSTRUCTURE
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
SIZE
TEMPERATURE RANGE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT ALLOYS