Enhanced piezoelectric and ferroelectric properties of tetragonal BiFeO3–BaTiO3 ceramics via tailoring sintering temperature and dwell time

The enhanced piezoelectric and ferroelectric properties of the tetragonal 0.67BiFeO 3 –0.33BaTiO 3 (BF–33BT) ceramics without MnO 2 doping or other dopants via tailoring sintering temperature ( T S ) and dwell time ( t d ) are reported. All ceramics crystallized in a single tetragonal phase, independent of the adopted T S and t d . As the T S or t d is increased, the BF–33BT ceramics show an increase in grain size and in relative density, while T S  > 980 °C or t d  > 6 h would result in more oxygen vacancies caused by Bi 3+ evaporation and/or reduction of Fe 3+ to Fe 2+ , along with a reduced relative density and an increased current leakage density. Because of the increased grain size, the higher relative density, and relatively less oxygen vacancies, high d 33  = 151 pC/N and P r  = 25.9 μC/cm 2 were achieved in tetragonal BF–33BT ceramics with T S  = 980 °C and t d  = 6 h. In addition, large unipolar strain of 0.146% and \(d_{33}^{*}\) =326 pm/V (40 kV/cm), as well as high T C  = 427 °C were also obtained in the BF–33BT ceramics with T S  = 980 °C and t d  = 6 h. Our studies indicate that the grain size, the relative density, and the oxygen vacancies play important roles for the piezoelectric properties of BF–33BT ceramics.