Electrical Properties and Relaxor Phase Evolution of Li‐Modified BNT‐BKT‐BT Lead‐Free Ceramics

Abstract

By conventional ceramics sintering technique, the lead-free 0.85Bi 0.5 Na 0.5(1 -x) Li 0.5x TiO 3 -0.11Bi 0.5 K 0.5 TiO 3 -0.04BaTiO 3 (x = 0-0.15) piezoelectric ceramics were obtained and the effects of Li dopant on the piezoelectric, dielectric, and ferroelectric properties were studied. With increasing Li addition, the temperature-dependent permittivity exhibited the normal ferroelectric-to-ergodic relaxor (FE-to-ER) transition temperature (T FE-ER , abbreviated as T F-R ) decreasing down to room temperature. The increasing Li content also enhanced the diffuseness of the FE-to-ER transition behavior. For composition with x = 0.15, a large unipolar strain of 0.37% (d à 33 = S max /E max = 570 pm/V) was achieved under 6.5 kV/mm applied electric field at room temperature. Both unipolar and bipolar strain curves related to the temperature closely, and when the temperature reached the T F-R , the normalized strain d

Giant electro‐strain in textured Li+‐doped 0.852BNT–0.11BKT–0.038BT ternary lead‐free piezoelectric ceramics

“…However, few systematical studies on the textured BNT‐BKT‐BT ternary ceramics, which show prominent piezoelectric properties near the morphotropic phase boundary (MPB), have been carried out to date. In addition, according to previous researches, the piezoelectric property of BNT‐BKT‐BT ceramics could be further enhanced by chemical doping . Therefore, by the combination of texturing and chemical modification, better electro‐strain performance can be obtained in BNT‐BKT‐BT ternary ceramics.…”

“…The textured samples were sintered at 1120°C for 10 hours. The preparation method of random BNKBT12Li was proposed in previous work …”

“…In addition, according to previous researches, the piezoelectric property of BNT-BKT-BT ceramics could be further enhanced by chemical doping. 22 Therefore, by the combination of texturing and chemical modification, better electro-strain performance can be obtained in BNT-BKT-BT ternary ceramics.…”

Evaluation of covalency of ions in lead-free perovskite-type dielectric oxides

“…The existing experimental results told us some difficulties in the fabrication by solid-state sintering because of vaporization of Bi, Na 2 O, K 2 O out of the materials, of which problem seemed settled in present, 21,24 and showed the boundaries and the effects for both systems. [21][22][23][24][25] Our results may be related to the boundaries in some chemical sense, and be utilized for the further chemical modification, which will eventually guide us to obtaining excellent lead-free actuators and energy harvesters.…”

Effect of chemical inhomogeneity on domains and ferroelectric properties of Fe‐modified 0.77Bi0.5Na0.5TiO3–0.23SrTiO3

“…One of their most important properties is the displacement induced by an electric field. Recently, the giant electric‐field‐induced strain of (Bi,Na)TiO 3 [BNT] based lead‐free ceramics has shed light on the potential to develop large‐stroke actuator applications, without the environmental issues of lead based materials . In particular, (Bi,Na)TiO 3 – x SrTiO 3 [BNT– x ST] ceramics have exhibited a strain response of 0.30% at a relatively low electric field, surpassing commercial Pb(Zr,Ti)O 3 .…”