Enhanced dielectric and piezoelectric performance of sol-gel derived (1-x) Bi0.5(Na0.78K0.22)0.5TiO3-xBaTiO3 ceramics

In this study, (1-x) Bi-0.5(Na0.78K0.22)(0.5)TiO3-xBaTiO(3) lead-free piezoelectric ceramics were prepared by sol-gel method. The effects of K+ doping modification and BaTiO3 solution modification on the microstructure and electrical properties of bismuth sodium titanate based ceramics were investigated. The modified samples show pure perovskite structure without impurities. The coexistence of rhombohedral phase and tetragonal phase was observed in the samples (x = 0.06-0.12), which was verified by lattice parameters and Raman spectrum analysis. The introduction of BaTiO3 reduced the grain size and increased the density of the sample. The maximum electrical parameters (epsilon(max) = 1887, d(33max) = 167 pC/N and kp(max) = 45%) of the sample (x = 0.06) are significantly higher than those of other references, and the temperature stability of piezoelectric constant was greatly improved. The related mechanism was analyzed in detail by lattice theory and domain theory.