Effect of synthesis process on the densification, microstructure, and electrical properties of Ca0.9Yb0.1MnO3 ceramics

Abstract

Ca0.9Yb0.1MnO3 thermoelectric materials have been prepared, through a classical solid‐state sintering method, from attrition‐ and ball‐milled precursors. After calcination step, microstructural observations have shown that attrition‐milled precursors possess much smaller particle sizes than the obtained by ball milling. Smaller precursors sizes lead to higher reactivity, producing higher density, hardness, and thermoelectric phase content in the sintered materials. The thermoelectric properties reflect the microstructural features, decreasing electrical resistivity in the attrition milling prepared samples without a drastic decrease in the Seebeck coefficient. As a consequence, power factor values are higher than the obtained in the classical solid‐state method samples. Moreover, the highest power factor values at 800°C are much higher than the best results obtained in this CaMnO3 family. As a result, it has been found that it is possible to tailor the thermoelectric properties of Ca0.9Yb0.1MnO3 ceramics by designing the appropriate preparation procedure while keeping in mind its industrial scalability.