Synthesis and piezoelectric properties of (Na0.5Bi0.5)0.94Ba0.06TiO3 ceramics prepared by sol–gel auto-combustion method

In this study, NaNO3, Bi(NO3)3·5H2O, Ba(NO3)2, Ti(OC4H9)4 and citric acid were successfully introduced to fabricate lead-free piezoelectric (Na0.5Bi0.5)0.94Ba0.06TiO3 [NBBT] nanopartical powders by a novel modified sol–gel auto-combustion method. The resultant products were characterized by the X-ray diffraction analysis and transmission electron microscope method. (Na0.5Bi0.5)0.94Ba0.06TiO3 + Mn(NO3)2 [NBBTM] can be sintered by the traditional solid-state reaction, and the effects of NBBT doped different amounts of Mn(NO3)2 at various sintering temperatures upon phase formation, microstructure as well as piezoelectric properties were further studied. The experimental results show that it was helpful to control their chemical ingredients and microstructure to prepare nanocrystalline single phase NBBT powders. Where is the X-ray diffraction result of the corresponding ceramics to prove the existence of the mixing between rhombohedral and tetragonal phases at the MPB compositions. Doping 0.015 mol% Mn(NO3)2 into NBBT at 1,090 °C, piezoelectric constant (d 33) and relative dielectric constant (er) reach the superior value of 159pC/N and 1,304, respectively, and dielectric loss (tan δ) and electromechanical coupling factor (K t) are 2.5% and 65%, respectively.