Effect of sintering temperature on structural, dielectric, piezoelectric and ferroelectric properties of sol-gel derived BZT-BCT ceramics

The effects of sintering temperature on the structural, dielectric, piezoelectric and ferroelectric properties of sol-gel derived lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) piezoelectric ceramics have been reported in this manuscript. BZT-BCT ceramics sintered at 1550 °C for 2 h resulted in homogeneous and highly dense microstructure with ~96-97% of the theoretical density and grain size of ~10 µm. The results indicated a strong influence of the sintering temperature on the structural, dielectric, piezoelectric and ferroelectric properties of BZT-BCT ceramics. BZT-BCT ceramics sintered at 1550 °C for 2 h resulted in high piezoelectric charge coefficient d33~617 pC/N, large planar electromechanical coupling factor kp~54%, large piezoelectric voltage constant g33~11.5 mV m/N, high dielectric constant εr~5000, and a low tan δ~0.019. The correlation of dielectric, piezoelectric and ferroelectric properties of the BZT-BCT ceramics with sintering temperature has been explained on the basis of grain size effect and motion of the 90° domain walls.