Phase diagram determination of large piezoelectric response in BHT-BCT ceramics

High-performance lead-free piezoelectric materials are environmentally friendly and in great demand for electronic devices. In this study, the phase diagram and properties of Hf, Ca co-doped BaTiO3 (BHT-BCT) were investigated. A triple-point morphotropic phase boundary separating the rhombohedral, tetragonal and cubic phases for the (1-x)Ba(Ti0.85Hf0.15)O-3-x(Ba0.7Ca0.3)TiO3 system exited at x = 0.3. High piezoelectric properties with piezoelectric coefficients d(33) (572pC/N) and Curie temperature T-c (90 degrees C) of 0.55Ba(Ti0.85Hf0.15)O-3-0.45(Ba0.7Ca0.3)TiO3 are achieved in the BaTiO3-based ceramics.