An improved direct current sintering technique for proton conductor — BaZr0.1Ce0.7Y0.1Yb0.1O3: The effect of direct current on sintering process

• Published in: Journal of power sources 2014, Vol.248, p.70-76
• Main Authors: Jiang, Taizhi, Liu, Yajie, Wang, Zhenhua, Sun, Wang, Qiao, Jinshuo, Sun, Kening
• Format: Article
• Language: English
• Subjects: Applied sciences; Conductors (devices); Constraining; Current density; Direct current; Electrolytes; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Grain size; Resistivity; Sintering
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.09.042

BaZr0.1Ce0.7Y0.1Yb0.1O3 (BZCYYb), a promising proton conductor of poor sinterability used in solid oxide fuel cells (SOFCs), has been densified in 1 h at 850 C using a direct current sintering technique (DC-sintering). Under a constant electrical field, the current density through the specimen of BZCYYb rises rapidly when the temperature increases to a certain value. In the DC-sintering process, the current density is restricted when the sharp increase occurs. By limiting current density to different values for 1 h, it is found that current density is the most important factor in the DC-sintering process. The conductivity and the grain size of the BZCYYb electrolyte increase significantly with the enhanced current density, while the different initial applied electrical fields have a negligible effect. The stable stage of DC-sintering process can be explained by Joule heating. The corresponding real temperature of the specimens is estimated by applying black body radiation theory.