Electrical conductivity and chemical stability of BaCe0·8 − xAxGd0·2O3 − δ (A = In, Zr, Ta; x = 0, 0·1) ceramics

BaCe0·8 − xAxGd0·2O3 − δ (A = In, Zr, Ta; x = 0, 0·1) ceramics were synthesized by solid-state reaction method. Microstructure and electrical properties of BaCe0·8 − xAxGd0·2O3 − δ ceramics were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and complex impedance analysis at intermediate temperatures of 573–1073 K in different atmospheres. BaCe0·8Gd0·2O3 − δ, BaCe0·7In0·1Gd0·2O3 − δ and BaCe0·7Zr0·1Gd0·2O3 − δ ceramics exhibit a single cubic perovskite structure. BaCe0·7In0·1Gd0·2O3 − δ ceramic has the highest conductivity of 4·6 × 10 − 2 S·cm − 1 in air at 1073 K. BaCe0·7In0·1Gd0·2O3 − δ and BaCe0·7Zr0·1Gd0·2O3 − δ ceramics exhibit an excellent chemical stability against boiling water. Indium is a suitable doping element to promote the sintering densification and to enhance both electrical conductivity and chemical stability of Gd-doped BaCeO3 at operating temperatures.