The electrical properties of microwave sintered gadolinia doped ceria–alumina nano-composite electrolyte

Gadolinia doped ceria–alumina (GDC–Al2O3) nano composites have been prepared by chemical synthesis route and sintered using 2.45 GHz microwave energy as well as conventional technique. The electrical properties of the sintered samples are investigated by ac impedance spectroscopy. It has been observed that the conductivity of microwave sintered GDC–Al2O3 composite is higher than that of conventional sintered GDC–Al2O3 composite and pure GDC sample. Higher concentration of vacancies at the interfaces of GDC and Al2O3 phases may be responsible for the better conductivity of GDC–Al2O3 composite compared to pure GDC. The fine grain microstructure of microwave sintered samples creates more interfaces compared to conventional sintered sample which in turn responsible for the better performance of microwave sintered composite sample. The micro-structural results of microwave sintered samples also reveal the presence of elongated, needle like Al2O3 grains. The X-ray diffraction results have shown the formation of additional GdAlO3 phase.