PREPARATION OF ND-DOPED BACEO3 PROTON-CONDUCTING CERAMIC AND ITS ELECTRICAL-PROPERTIES IN DIFFERENT ATMOSPHERES

Nd-doped BaCeO3 was prepared by a conventional ceramic processing tech nique using a special procedure to reduce calcining and sintering temp eratures and to avoid possible contamination. BaCe0.9Nd0.1O3-alpha sin gle perovskite phase was formed when the mixture powders was calcined at T greater than or equal to 1000 degrees C. Ball-milling of the calc ined powders could well disperse agglomerates. Sintered at T greater t han or equal to 1300 degrees C, specimens with density greater than or equal to 93% of the theoretical and without open porosity could be ob tained. Electrical conductivity was measured in different dry atmosphe res of Ar, air and O-2 and in moist air. The results showed that in dr y Ar, air and O-2, the conductivity values at a given temperature were similar, and the activation energies almost identical, possibly becau se Nd-doped BaCeO3 demonstrated predominately oxygen ion conduction in these environments. In moist air, proton conduction might predominate , leading to an increase in conductivity and a decrease in activation energy. (C) 1998 Elsevier Science Limited. All rights reserved.