Thermoelectric properties of $ Ca_{3} %$ Co_{4} %$ O_{9} $ ceramics

Abstract $ Ca_{3} %$ Co_{4} %$ O_{9} $ ceramics were prepared using the sol-gel process with ordinary pressing sintering and their thermoelectric properties were measured from room temperature to 673 K. The experimental results show that single phase $ Ca_{3} %$ Co_{4} %$ O_{9} $ can be fabricated a...
Ausführliche Beschreibung

Abstract $ Ca_{3} %$ Co_{4} %$ O_{9} $ ceramics were prepared using the sol-gel process with ordinary pressing sintering and their thermoelectric properties were measured from room temperature to 673 K. The experimental results show that single phase $ Ca_{3} %$ Co_{4} %$ O_{9} $ can be fabricated at 750–900 °C in different citrate acid molar proportions for 0.2–1.0. For all the oxides, both the Seebeck coefficients S and the electrical conductivities κ increase with the increasing temperature. The Seebeck coefficients S are all positive. The thermal conductivities k increase with the increasing temperature also and the lattice thermal conductivity κl plays an important role to the thermal conductivity κ. The citrate acid molar proportions have a large influence on the particle sizes, which influences the thermoelectric properties of the ceramics. The figure of merit increases with the increasing temperature and reaches 4.5×$ 10^{−5} $ $ K^{−1} $ at 573 K for the sample in the citrate acid molar proportion of 0.46. Ausführliche Beschreibung