Significant Development of the Thermoelectric Materials in Effect of Hot-Pressing Process on Ca3Co4O9

Abstract: This work explores the prospects for a further enhancement of the thermoelectric properties of Ca3Co4O9 with hot-pressing. The modified hot-pressing process resulted in highly textured and dense ceramics. This paper describes the synthesis process to make dense pellets from the Indian made hot press system. This paper reports a novel composite-based processing route for improving the electrical performance of Ca3Co4O9 thermoelectric (TE) ceramics. In this study, highly textured ceramics of Ca3Co4O9 were fabricated by solid state methods and hot-pressing (HP) was used to increase the density and reduce porosity from pellets so that we get dense thermoelectric materials for measurements. Thermoelectric Ca3Co4O9 Calcium Cobalt Oxide 820mm circular pellets have been prepared successfully by the Hot pressed method, expectedly sintered, and their thermoelectric properties, in which the density is approximately the same as the theoretical value. XRD of Sintered pellets well matched with JCPDS data. FESEM images show the compactness of circular pellets where porosity is reduced between molecules, excellent for thermoelectric measurements. Keywords: Ceramics; Oxides; Hot-pressing; Texture; Electrical properties, Ca3Co4O9, Ca3Co2O6, Two-step sintering, Thermoelectric property, Mixture