Piezoelectric and dielectric properties of La2O3 added Bi(Na, K)TiO3–SrTiO3 ceramics for pressure sensor application

In this study, piezoelectric and dielectric properties of lead-free Bi(Na, K)TiO3–SrTiO3 (abbreviated as BNKT–ST) system piezoelectric ceramics were investigated for pressure sensor applications as a function of the amount of La2O3 addition. With increasing the amount of La2O3 addition, density and dielectric constant increased up to 0.9 wt.% La2O3 and decreased above 0.9 wt.% La2O3. Electromechanical coupling factor (kp) showed the maximum value at 0.2 wt.% La2O3 and decreased above 0.2 wt.% La2O3. Electromechanical coupling factor (kp), density, dielectric constant (ɛr), piezoelectric constant (d33) and curie temperature (Tc) were showed the optimum value of 0.40, 5.75 g/cm3, 768, 215 pC/N and 320 °C at 0.2 wt.% La2O3, respectively. The output voltage of the pressure sensor showed 0.48 V at 20 in H2O.