BICOVOX: Sintering and grain size dependence of the electrical properties

The sintering conditions and the effects of the mean grain size on the elec trical properties of cobalt-substituted bismuth vanadate (Bi2V0.9Co0.1O5.35 ), referred to as BICOVOX, have been studied. The influence of the experime ntal conditions (sintering temperature and duration, oxygen partial pressur e) on the resulting density of the pellet was evaluated by dilatometric mea surements. The grain size dependence of the electrical properties was studi ed by impedance spectroscopy. It is shown that the BIMEVOX characteristic h ysteresis, which results in a significant decrease of the ionic conductivit y below about 450 degrees C, is suppressed provided that the grain size is small enough. (C) 1999 Elsevier Science Limited. All rights reserved.