Preparation, microstructure and relaxor ferroelectric characteristics of BLNT-BCT lead-free piezoceramics

- First time, we synthesized 1-xBLNT-xBCT ceramics system with x ≤ 0.20 by semi wet technique.
- XRD and Raman spectroscopy revealed the phase transformation with x.
- Grain size reduced with doping x and BCT acts as an inhibitor in the grain growth.
- Dielectric plots exhibited a broad frequency dependent maximum upto x ≤ 12 near Tm.
- Dielectric/piezoelectric/electromechanical properties greatly enhanced with optimum x.

In the present study, lead-free piezoelectric (1-x)[(Bi0.96La0.04)0.5Na0.5TiO3]-(x)[Ba0.90Ca0.10TiO3] ceramics with x ≤ 0.20 have been prepared at optimum temperature (950°C-1050 °C) by employing semi-wet technique. The effect of Ba0.90Ca0.10TiO3 (BCT) content on the phase formation, surface morphology, dielectric and piezoelectric properties is systematically investigated and characterized by X-ray diffraction (XRD), Raman Spectroscopy, Field emission Scanning electron micrographs (FE-SEM), Impedance analyzer. XRD analysis shows phase transformation from rhombhohedral to tetragonal with the addition of BCT and the average grain size decreases with BCT content, x. Temperature dependent dielectric behavior exhibits two phase transitions, i.e. depolarization temperature; Td and phase transition temperature; Tm. The phase transitions; Tm tends to diffuse with increasing x and exhibited a broad frequency dependent maximum upto x ≤ 12. Optimum piezoelectric and dielectric properties (i.e., d33 = 165 pC/N, kp = 39%, kt = 47% and k33 = 57%, εr = 1585, tan δ = 0.07) in the studied system have been obtained.