Textured Ca3Co4O9 ceramics were prepared by a reactive templated grain growth process using tape casting process. The effect of the solid loading of the green tape on the thermoelectric properties of the textured Ca3Co4O9 was investigated. The findings indicate that the thermoelectric properties of textured ceramics are dependent on the solid loading of cast tapes. The power factor (S2 σ) for Ca3Co4O9 can be optimized by appropriately controlling the solid loading, because the electric conductivity (σ) is susceptible to variations in the bulk density by the solid loading, whereas the Seebeck coefficient (S) is relatively insensitive to this type of variation. The maximum power factor for textured Ca3Co4O9 ceramics with a solid loading of 62.2 vol% was 4.52 × 10-4 W/mK2 at a temperature of 1100 K.

Keywords: Reactive templated grain growth, Spark plasma sintering, Solid loading, Ca3Co4O9.