Effects of BLT doping on electrical properties and relaxation behavior of BCZT-BLT ceramics

The (1 − x)(Ba_0.85Ca_0.15)(Ti_0.90Zi_0.10)O₃ − x(Bi_0.50Li_0.50)TiO₃ [(1 − x)BCZT − xBLT, x = 0, 0.1, 0.2, 0.3 and 0.4%] lead-free ferroelectric samples were fabricated by a conventional solid-state sintering method and the effects of BLT addition on their microstructure, electrical properties, and dielectric relaxation behaviors have been investigated. Experimental results show that the BLT doping can dramatically reduce the sintering temperature of BCZT from 1540 °C to 1400 °C and enhance piezoelectric properties. Moreover, the XRD patterns show that the ceramics are with the perovskite structure, and no other impurity peaks are clearly observed. A certain number of block-shaped grains is seen from TE-SEM images and elements mapping exhibit that calcium and zirconium elements distribute unevenly. The temperature-dependent dielectric performance testing results present that all the samples possess obvious relaxation behavior. The ceramic sample is with an optimum performance at x = 0.2% of (1 − x)BCZT − xBLT, where d₃₃ = 420pC/N, k_p = 50%, ε_r = 4134, tanδ = 0.015, T_c = 81.5 °C , and γ = 1.76, respectively. Hence they could serve as a potential replacement for the lead-based piezoelectric ceramics.