SYNTHESIS OF Na_xCo_2O_4 THERMOELECTRIC OXIDE BY THE POLYMERIZED COMPLEX METHOD AND SPS METHODS

摘要

The Na_xCo_2O_4 thermoelectric oxide was synthesized by the polymerized complex (PC) process and SPS method. The effects of the PC and SPS method on the microstructure and thermoelectric properties of the sintered body were investigated. The PC+SPS sample had a quite fine microstructure and high density as compared to the sample prepared by the conventional solid state reaction (SSR) method. However, the crystallographic anisotropy of the sintered body was deteriorated during SPS because of the short sintering time of SPS and partial decomposition of the Na_xCo_2O_4 phase. The power factor of the PC+SPS sample was quite larger than that of the conventional SSR sample.