High temperature phase diagram of pseudo binary Ba(Zr0.2Ti0.8)O3-(Ba0.7Ca0.3)TiO3 ceramic system: In situ X-ray diffraction and dielectric studies

Abstract

ABSTRACTLead free perovskite Ba(Zr0.2Ti0.8)O3-(Ba0.7Ca0.3)TiO3 is considered to be one of the most studied system for piezoelectric and energy harvesting applications. Present work reports the temperature dependent X-ray diffraction and dielectric properties of perovskite (1-x)Ba(Zr0.2Ti0.8)O3–x(Ba0.7Ca0.3)TiO3 ceramic system prepared using a standard high-temperature solid-state reaction method. Dielectric studies showed two dielectric relaxations. The lower phase transition ranged between −10°C (x = 0) to 85°C (x = 1) whiles the high temperature phase transitions, diffusive in character occur from 575°C (x = 0) to 620°C (x = 1), which places the present ceramic system in the list of potential candidate for high temperature applications. The high temperature phase transitions in the system were well supported by in situ X-ray diffraction studies. X-ray diffraction analyses indicated that the present system have a perovskite-type monoclinic (space group: P2/m) at high temperatures. Phase transition behaviour has been illustrated in the form of a temperature-composition phase diagram of BZT-xBCT system.