Lead-free (K0.5Bi0.5)TiO3 powders and ceramics prepared by a sol–gel method

A lead-free ferroelectric material, (K0.5Bi0.5)TiO3 (KBT), was prepared by a sol–gel process. Thermal analysis and X-ray diffraction showed that perovskite KBT powders with a grain size of 100–200 nm were obtained by calcining dried gels above 700 °C. When the calcining temperature was lower than 650 °C, only the Bi2Ti2O7 phase was found in the X-ray diffraction patterns. Moreover, KBT ferroelectric ceramics was fabricated by traditional sintering of as-prepared KBT powders. The KBT ceramics sintered at 1050 °C showed a high density (91.2% of theoretic density) and low dielectric loss, better than that prepared by a solid-state reaction method. The temperature dependence of dielectric permittivity of KBT ceramics showed a Curie temperature at 385 °C.