Effect of oxygen activity on Nb solubility in BaTiO3

This paper describes the effect of oxygen partial pressure on Nb solubility in polycrystalline BaTiO3 at 1673 K. It was found that an increase of p(O- 2) in the gas phase results in an increased Nb solubility in BaTiO3. Anneal ing of polycrystalline BaTiO3, covered with a thin layer of NbCl5, in air a t 1573 K results in Nb incorporation to the level of 0.1 at.% while anneali ng at the same temperature in nitrogen (involving 2% H-2) does not lead to Nb incorporation into BaTiO3. The observed effect of p(O-2) on Nb solubilit y in BaTiO3 is consistent with the defect disorder model of BaTiO3. (C) 200 1 Elsevier Science Ltd. All rights reserved.