The effect of B2O3 addition on the sintering of Sb2O3 doped BaTiO3

Abstract

The effect of 0.5, 1.0, 2.0 mol% B2O3 additions on the microstructure and densification of BaTiO3 (Ba/Ti=0.98) + 0.0025 mol% Sb2O3 were investigated. The BaTiO3 powders were prepared by the conventional ceramic processing method. The samples were sintered at different temperatures between 1200 to 1360 degreesC for 1 hour. Generally, low temperature sintering of the TiO2 excess compositions below the eutectic temperature of 1332 degreesC results in a characteristic platelet-type grained microstructure. This platelet structure was found to be the Ba2Ti5O12 phase in the undoped BaTiO3 (Ba/Ti=0.98) and in the 0.5 mol% B2O3 added samples sintered up to 1335 T. Suppression of these platelet-type grains occurred in the B2O3 additions above 0.5 mol%. A second-phase precipitate of boron containing compounds was not detected by XRD. The maximum theoretical density of 98% was obtained in the Sb2O3 doped BaTiO3 samples sintered at 1275 T and in the 0.5 mol% B2O3 added samples sintered at 1300 degreesC for 10 hours reaching the 96% T.D. The bulk densities of the sintered samples decreased with the increasing B2O3 content due to the high porosity trapped between the grains.