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Thermal expansion studies of selected high temperature thermoelectric materials

Show simple item record Ravi, Vilupanur Firdosy, Samad Caillat, Thierry Brandon, Erik Van Der Walde, Keith Maricic, Lina Sayir, Ali 2015-07-01T17:16:18Z 2015-07-01T17:16:18Z 2008-08-03
dc.identifier.citation International Conference on Thermoelectrics, Corvallis, Oregon, August 3-7, 2008 en_US
dc.identifier.clearanceno 09-0303
dc.description.abstract Radioisotope thermoelectric generators (RTGs) generate electrical power by converting the heat released from the nuclear decay of radioactive isotopes (typically plutonium-238) into electricity using a thermoelectric converter. RTGs have been successfully used to power a number of space missions and have demonstrated their reliability over an extended period of time (tens of years) and are compact, rugged, radiation resistant, scalable, and produce no noise, vibration or torque during operation. System conversion efficiency for state-of-practice RTGs is about 6% and specific power ≤ 5.1 W/kg. Higher specific power would result in more on-board power for the same RTG mass, or less RTG mass for the same on-board power. The Jet Propulsion Laboratory has been leading, under the advanced thermoelectric converter (ATEC) project, the development of new high-temperature thermoelectric materials and components for integration into advanced, more efficient RTGs. Thermoelectric materials investigated to date include skutterudites, the Yb₁₄MnSb₁₁ compound, and SiGe alloys. The development of long-lived thermoelectric couples based on some of these materials has been initiated and is assisted by a thermo-mechanical stress analysis to ensure that all stresses under both fabrication and operation conditions will be within yield limits for those materials. Several physical parameters are needed as input to this analysis. Among those parameters, the coefficient of thermal expansion (CTE) is critically important. Thermal expansion coefficient measurements of several thermoelectric materials under consideration for ATEC are described in this paper. The stress response at the interfaces in material stacks subjected to changes in temperature is discussed, drawing on work from the literature and project-specific tools developed here. The degree of CTE mismatch and the associated effect on the formation of stress is highlighted. en_US
dc.description.sponsorship NASA/JPL en_US
dc.language.iso en_US en_US
dc.publisher Pasadena, CA : Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2008 en_US
dc.subject silicon germanium en_US
dc.subject zintl en_US
dc.title Thermal expansion studies of selected high temperature thermoelectric materials en_US
dc.type Preprint en_US

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