A phase diagram of Ba_1-xCa_xTiO₃ (x = 0-0.30) piezoceramics by Raman spectroscopy

Piezoelectric ceramics are widely used in sensors, actuators, and ultrasonic transducers due to their ability to achieve efficient conversion between electric and mechanical energy. There is a current drive toward lead-free material systems capable of achieving comparable piezoelectric performance to environmentally hazardous, but commonly used, lead-based materials such as lead zirconate titanate. This work constructs an accurate phase diagram for barium calcium titanate (Ba1-xCaxTiO3 or BCTO). The substitution of Ca2+ on the Ba-site of BCTO is of much interest due to electric property improvements compared to BaTiO3. In this work, Ba1-xCaxTiO3 (x = 0-0.30) samples have been made by solid-state methods and, following initial characterization by X-ray diffraction (XRD), evaluation of changes in the Raman spectra has allowed accurate determination of the phase transition temperatures and the construction of a phase diagram.