Effect of process condition on the ferroelectric properties in BiFeO3-(Bi,K)TiO3 ceramics

The Effects of the sintering temperature on the physical and the ferroelectric properties were investigated in 0.6BiFeO3-0.4(Bi0.5K0.5)TiO3 (0.6BF-0.4BKT) ceramics. 0.6BF-0.4BKT ceramics were fabricated by using a solid-state reaction and the calcined powders were pulverized by ball milling (BM) or attrition milling (AM). A single perovskite phase with a pseudo-cubic diffraction pattern was observed in the samples sintered at 950~1,050 °C. The AM ceramic sintered at 950 °C showed a density of about 93% the theoretical density while the BM ceramic sintered at temperature above 1,000 °C displayed a density larger than 90% the theoretical value. The BF-BKT ceramic had dielectric properties with stable frequency characteristics of and a well-saturated P-E hysteresis when sintered at temperatures higher than 1,000 °C in the BM sample and higher than 950 °C in the AM sample. Dielectric relaxations around 200 Hz and leaky P-E loops were observed in BF-BKT ceramics sintered at lower temperatures.