Electrical conductivity and chemical stability of BaCe_(0.8-x)A_xGd_(0.2)O_(3-δ) (A = In, Zr, Ta; x = 0,0.1) ceramics

摘要

BaCe_(0.8-x)A_xGd_(0.2)O_(3-δ) (A = In, Zr, Ta; x = 0, 0-1) ceramics were synthesized by solid-state reaction method. Microstructure and electrical properties of BaCe_(0.8-x)A_xGd_(0.2)O_(3-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. BaCe_(0.8)Gd_(0.2)O_(3-δ), BaCe_(0.7)In_(0.1)Gd_(0.2)O_(3-δ) and BaCe_(0.7)Zr_(0.1)Gd_(0.2)O_(3-δ) ceramics exhibit a single cubic perovskite structure. BaCe_(0.7)In_(0.1)Gd_(0.2)O_(3-δ) ceramic has the highest conductivity of 4-6 × 10~(-2) S-cm~(-1) in air at 1073 K. BaCe_(0.7)In_(0.1)Gd_(0.2)O_(3-δ) and BaCe_(0.7)Zr_(0.1)Gd_(0.2)O_(3-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 BaCeO_3 at operating temperatures.