MICROSTRUCTURAL DEVELOPMENT ON FIRING NB2O5 AND BI2O3 DOPED BATIO3

Temperature stable dielectrics can be made by doping BaTiO3 with Nb2O5 and Bi2O3. During heating to the sintering temperature these three ph ases react to form Ba4Bi2Ti4Nb6O30 which has the tetragonal tungsten b ronze crystal structure and plays a significant role in the developmen t of the core-shell microstructure partly responsible for the temperat ure stable behaviour. The characterisation of this previously unknown phase is described and it is also shown to be a relaxor ferroelectric.