Issue 94, 2014

Sintering behavior and thermoelectric properties of LaCoO3 ceramics with Bi2O3–B2O3–SiO2 as a sintering aid

Abstract

Recently, LaCoO3 has received increasing attention as a promising thermoelectric oxide. However, its sintering temperature is too high from the practical point of view. This study investigated the effect of Bi2O3–B2O3–SiO2 (BBS) as a sintering aid on the low-temperature sintering behaviors, microstructures and thermoelectric properties of LaCoO3 ceramics. The XRD results revealed that the LaCoO3 ceramics with 1–3 wt% BBS could form a single crystalline phase without visible secondary phases. The sintering temperature of LaCoO3 ceramics was reduced remarkably from 1200 °C to 950 °C by adding 3 wt% BBS, with a relative density higher than 95%. The process of densification and the appearance of rod-like grains in LaCoO3 with BBS aids were observed by SEM. Meanwhile, the thermoelectric properties of LaCoO3 ceramics were strongly dependent on the densification and microstructures. For the samples sintered at 1050 °C, the electrical conductivity increased significantly with the increase of BBS content (x, wt%) up to x = 2.0, and the Seebeck coefficients were almost the same when the test temperatures were higher than 200 °C. Moreover, the sample with x = 2.0 had the optimum thermoelectric properties with ZT = 0.05 at 400 °C, which was about 66.7% higher than that of pure LaCoO3 ceramics sintered at 1200 °C, indicating that the addition of BBS could effectively promote the densification and further improve thermoelectric properties of LaCoO3 ceramics without using complicated processes.

Graphical abstract: Sintering behavior and thermoelectric properties of LaCoO3 ceramics with Bi2O3–B2O3–SiO2 as a sintering aid

Article information

Article type
Paper
Submitted
11 Jul 2014
Accepted
07 Oct 2014
First published
08 Oct 2014

RSC Adv., 2014,4, 51995-52000

Author version available

Sintering behavior and thermoelectric properties of LaCoO3 ceramics with Bi2O3–B2O3–SiO2 as a sintering aid

J. Han, Y. Song, X. Liu and F. Wang, RSC Adv., 2014, 4, 51995 DOI: 10.1039/C4RA06735E

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