Highly-dense and textured Ca 3Co 4O 9 ceramic samples were obtained by a spark plasma sintering (SPS) process. The sintering conditions were modified to optimize the degree of orientation and the bulk densities which are important for their thermoelectric performance. Their thermoelectric properties were measured from room temperature to 1,180 K in air. The maximum power factor was achieved at 1,153 K in the SPS-sintered case because of the maximum electrical conductivity owing to both the degree of orientation and bulk density. In order to improve the thermoelectric performance of this SPS-sintered Ca 3Co 4O 9 system a doping effect with various dopants was also investigated. Ca 3Co 4O 9 samples doped with Ag, Bi, and Na were prepared. Three factors including acceptor doping, a grain boundary phase and elevated mobility caused enhanced electrical conductivities. And these increased electrical conductivities resulted in increased power factors.
|Number of pages||5|
|Journal||Journal of Ceramic Processing Research|
|Publication status||Published - 2012 Jul 19|
All Science Journal Classification (ASJC) codes
- Ceramics and Composites