The Bi-layer structure bismuth 0.8 Bi0.5K0.5TiO3-0.2 BaTiO3 + x wt% (0.8 BKT-0.2 BT3-x, x = 0, 1, 2, and 3) Bi2O3 ceramic was sintered in air for 2 h from 1000°C to 1100°C. The excess content of Bi2O3 was used as the sintering aid and to compensate the vaporization of Bi2O3 during the sintering process. A narrow range of sintering temperature could be used to densify the 0.8 BKT-0.2 BT3-x ceramics. The addition of excess Bi2O3 would lower down the sintering temperature and extend the temperature range to sinter the 0.8 BKT-0.2 BT3-x ceramics. The Curie temperatures of 0.8 BKT-0.2 BT3-x ceramics would be shifted to lower temperatures as the sintering temperatures and the content of excess Bi2O3 increase.
