Dependence of Microstructure Induced with Manufacturing Parameters and Physical Properties of Compound of Skutterudite Structure Type Ce_xFeCo_3Sb_(12)

摘要

The skutterudites from Ce_xFeCo_3Sb_(12) series, where x = 0.3, 0.6, 0.9 and 1, were analyzed. The microstructure investigation indicates that increase of alloying duration clearly improves the chemical homogeneity of the compounds. The type of protective medium (acetone or argon), used during alloying, has been found to influence mainly the phase purity of obtained compounds. Precipitations of antimony are smaller in the compounds prepared in liquid environment. The existence of various oxide contaminations depends also on the type of protective medium used. In the compounds alloyed in acetone distribution of oxygen was evidently correlated with iron, whereas in compounds produced in argon cerium is partially oxidized. Temperature dependences of Seebeck coefficient and electrical resistivity were measured in temperature range from 300K to 780K. Beside the influence of the composition of a compound, also the influence of its microstructure on the values of thermoelectric power factor (PF) and temperature of its maximum has been observed. The compounds prepared in argon exhibit several times larger maximum values of PF. Regardless of the protective medium used, the highest values of PF always were obtained for compounds with the lowest Ce content.