The temperature-dependent coefficient of thermal expansion of p-type Ce0.9Fe3.5Co0.5Sb12 and n-type Co0.95Pd0.05Te0.05Sb3 skutterudite thermoelectric materials
- Michigan State University, East Lansing
- ORNL
During waste heat recovery applications, thermoelectric (TE) materials experience thermal gradients and thermal transients, which produce stresses that scale with the TE material's coefficient of thermal expansion (CTE). Thus, the temperature-dependent CTE is an important parameter for the design of mechanically robust TE generators. For three skutterudite thermoelectric compositions, n-type Co{sub 0.95}Pd{sub 0.05}Te{sub 0.05}Sb{sub 3} (with and without 0.1 at. % cerium doping) and p-type Ce{sub 0.9}Fe{sub 3.5}Co{sub 0.5}Sb{sub 12}, the CTE was measured using two methods, i.e. X-ray diffraction on powder and bulk specimens and dilatometry on bulk specimens. Each bulk specimen was hot pressed using powders milled from cast ingots. Between 300 K and 600 K, the mean CTE values were 9.8-10.3 x 10{sup -6} K{sup -1} for the non-cerium-doped n-type, 11.6 x 10{sup -6} K{sup -1} for the 0.1 at. % cerium-doped n-type and from 12.7 to 13.3 x 10{sup -6} K{sup -1} for the p-type. In the literature, similar CTE values are reported for other Sb-based skutterudites. For temperatures >600 K, an unrecovered dilatational strain (perhaps due to bloating) was observed, which may impact applications. Also, the submicron particle sizes generated by wet milling were pyrophoric; thus, during both processing and characterization, exposure of the powders to oxygen should be limited.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Temperature Materials Lab. (HTML)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1050274
- Journal Information:
- Philosophical Magazine, Vol. 92, Issue 10; ISSN 1478-6435
- Country of Publication:
- United States
- Language:
- English
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