Determining the effect of Ru substitution on the thermal stability of CeFe_(4-x)Ru_xSb_(12)

摘要

The ternary, rare-earth filled (RE) Skutterudites (REM_4Pn_(12); M = Fe—Os; Pn = P-Sb) have been proposed for use in high-temperature thermoelectric devices to convert waste heat to useful power. CeFe_4Sb_(12) has been one of the most popular materials proposed for this application; however, it oxidizes at relatively low temperatures. The thermal stability of Skutterudites can be enhanced by selective substitution of the constituent elements and Eu(Fe,Ru)_4Sb_(12) variants have been found to oxidize at temperatures above that of CeFe_4Sb_(12). Unfortunately, these materials have poor thermoelectric properties. In this study, the thermal stability of CeFe_(4-x)Ru_xSb_(12) was examined depending on the value of x. (These compounds have similar thermoelectric properties to those of CeFe_4Sb_(12).) It has been found by use of TGA and XANES that the temperature at which point CeFe_(4-x)Ru_xSb_(12) oxidizes increases with greater Ru substitution. XANES was also used to confirm the general charge assignment of Ce~(3+)Fe_(4-x)~(2+)Ru_x~(2-)Sb_(12)~(1-).