Thermoelectric properties of highly oriented Ca_2.7Bi_0.3Co₄O₉ fabricated by rolling process

Abstract

Highly oriented, Bi-substituted Ca₃Co₄O₉(Ca_2.7Bi_0.3Co₄O₉) was processed by the rolling method and its thermoelectric properties were investigated. The electrical conductivity (σ), Seebeck coefficient (α), thermal conductivity (k) and ZT value at 870 K were 123.4 S/cm, 172.7 μV/K, 2.1 W/mK, and 0.152, respectively. The electrical conductivity was about 1.5 times higher than that of a conventionally sintered sample. This rolling process is a very powerful method to produce a plate-like particle orientation in a ceramic microstructure and will be useful in the mass production of thermoelectric elements in powder injection molding (PIM).