Influence of sintering temperature on properties of BNKLLT–6 wt% BCTZ binary lead-free piezoelectric ceramic prepared through the solid-state combustion technique

In this work, a new binary 94 wt%[Bi_0.5(Na_0.68K_0.22Li_0.1)_0.5TiO₃ + 0.10 wt% of La₂O₃]–6 wt% [(Ba_0.85Ca_0.15)(Ti_0.90Zr_0.10)O₃] [BNKLLT–6 wt% BCTZ] ceramic was fabricated by the solid-state combustion technique and glycine was used as the fuel. The effect of sintering temperature in the range of 1075–1175 °C for 2 h on phase evolution, microstructure and electrical properties was investigated. The phase formation exhibited a coexistence structure between rhombohedral and tetragonal at low sintering temperature. As the sintering temperature increased, the phase formation changed to pseudo-cubic phase. The average grain size of the ceramics was increased with the increasing sintering temperature. Density, ?_r, ?_SA and T_FA of BNKLLT–6 wt% BCTZ ceramics increased while the T_SA decreased when the sintering temperature increased up to 1125 °C, while after this temperature the opposite trends occurred. At a sintering temperature of 1125 °C, the BNKLLT-6 wt% BCTZ sample showed the highest theoretical density (95.8%), maximum dielectric constant ?_SA (5278), highest d₃₃ (227 pC/N) and fair ferroelectric properties (P_r = 24.5 µC/cm² and E_c = 15.45 kV/cm).