High Temperature Thermoelectric Properties of Oxide Ca<sub>2</sub>Co<sub>2</sub>O<sub>5</sub>

Ca2Co2O5 ceramic powders were synthesized by the coprecipitation method and consolidated by spark plasma sintering (SPS) technique.The observation by the SEM indicated that the ceramics body showed fine and layer microstructure.The density of the body increased with an increase of the fritting temperature.XRD patterns showed that the ceramics sample exhibits inpure phase with increasing the sintering temperayure to 850°C and that the grain was preferentially oriented.The electrical conductivity was reduce and the Seebeck coefficient slightly increased with an increase of the sintering temperature.As a result,the thermoelectric properties of the sample prepared by SPS at 800 °C for 5 min was better than the sample prepared by SPS at 750 °C for 5 min at high temperature.The sample treated by the SPS process under the condition of 800 °C,40 MPa and 5 min showed the maximum power factor (PF) of 3.85×10-4W∙m-1∙K-2 at 923 K.