Abstract
Ca3-xSrxCo4-yCuyO9+δ (x=0, 0.1, 0.3; y=0, 0.05, 0.1) samples were prepared by using a conventional ceramic method. The crystal structure, bulk density and thermoelectric properties of the samples were investigated. In the X-ray diffraction patterns of the samples sintered at 1100°C, the single phase of Ca3Co4O9+δ was obtained. Lattice constants were increased with x and y, which suggested that Sr and Cu were substituted for Ca and Co in the Ca3Co4O9+δ structure, respectively. The sample with x=0.3 and y=0.1 got the highest density because the grain size bacame small and the void was removed.
The highest density sample had the highest conductivity in all samples. The Seebeck coefficient didn't change by substitution. As a result, the sample with x=0.3 and y=0.1 had the highest power factor in all samples because of increase of the conductivity by substitution.
