Synthesis and Thermoelectric Properties of Ce_yRu_xIr_(4-x)Sb_(12) Filled Skutterudite Compounds

摘要

Radioisotope Thermoelectric Generators (RTGs) have proved to be reliable, long-lived sources of electrical power that have enabled the conduct of a number of important NASA deep space missions since 1961. Past RTGs have used two types of thermoelectric materials: PbTe/TAGS and SiGe. In an effort to further improve both the thermoelectric efficiency and specific power of the next generation of RTGs, JPL is investigating a number of potential high-efficiency, high-temperature thermoelectric materials that could operate at a hot-side temperature of up to 1275 K. Among the materials being studied are the refractory Ce_yRu_(4-x)Ir_xSb_(12) filled skutterudite compounds. We have synthesized polycrystalline samples for x ≤ 1.5 by a powder metallurgy technique. Dense samples have been hot-pressed from the pre-reacted powders and characterized by a variety of techniques including electron probe microanalysis, differential thermal analysis and thermogravimetic analysis. Seebeck coefficient, electrical resistivity, Hall coefficient, and thermal conductivity measurements have been conducted on the samples from room temperature to 1275 K. Results show that the samples are phase stable up to 1275 K. The results of the transport property measurements are presented and discussed.