ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 38, Number 4
JKCSEZ 38(4)
August 20, 1994 

The stable defect structure and the single phase region of La2O3-modified BaTiO3 have been studied by X-ray diffractometer and scanning electron microscope. The stable defect structure of La2O3-modified BaTiO3 has been identified as [(BaxBa)1-2x(La·Ba)x][TixTi)1-x/2(V""Ti)x/2]O3 which consists of La3+ ion substitution for Ba3+ ion in the lattice structure and the formation of Ti vacancies for the charge compensation. When 3 mol% of La2O3·3/2TiO3 was added to BaTiO3, the unit cell structure was transformed from tetragonal to cubic and the solubility limit was about 14 mol%. When La2O3·3/2TiO2 was added above this solubility limit, the second phase, La4Ba2Ti5O18, was formed. In the La2O3-modified BaTiO3, it was found by the liquid phase sintering process that the sinterability was decreased by excess BaO but increased by excess TiO2.