In this work, the effects of (Ba_0.8Ca_0.2)TiO₃ (abbreviation BCT) addition on microstructure and electrical properties of (0.9-x) (Bi_0.5Na_0.3K_0.2)TiO₃-x (Ba_0.8Ca_0.2)TiO₃-0.1BiFeO₃ Pb-free ceramics (x = 0.0, 0.025, 0.05, 0.075, and 0.1) were investigated. Single-phase perovskite structure and high density have been obtained in all sintered ceramics. The crystal structure was found to change from tetragonal ferroelectric to pseudo-cubic relaxor with a modification in the grain morphology from cubic to round shape with increasing BCT content. Rietveld refinement was performed for detection of the morphotropic phase boundary formed (MPB). The phase crossover is caused by lattice distortion and oxygen vacancies at high content of BCT. In situ phase formed and domain structure-dependent temperature were researched by XRD and TEM, from RT-400 °C. The domain structure was observed to change from ferroelectric polar micro-region (PMR) at RT to relaxor polar nano-region (PNR) at 200 °C caused by compositional fluctuation and then to paraelectric phase at 400 °C. And the results were confirmed by XRD at diff T. Enhanced dielectric properties with highest permittivity value were achieved at x = 0.075 due to form MPB. High value of remnant polarization (Pr = 37 µC/cm²) and low value of coercive field (18 kV/cm) were observed at x = 0.075 due to the introduction of BCT. Four peaks were found in the current–electric field behavior (I-E) loops of all ceramics testifying the presence of electric-field-induced transitions.

在这项工作中，（Ba组成的影响_0.8钙_0.2）的TiO ₃（缩写BCT）的加入对（0.9-的微观结构和电特性X）的（Bi _0.5的Na _0.3 ķ _0.2）的TiO ₃ - X（BA _0.8钙_0.2）的TiO ₃ -0.1BiFeO ₃无铅陶瓷（x = 0.0、0.025、0.05、0.075和0.1）。在所有烧结陶瓷中均获得了单相钙钛矿结构和高密度。发现晶体结构从四方铁电体变为准立方弛豫体，随着BCT含量的增加，晶粒形态也从立方形变为圆形。进行Rietveld精修以检测形成的同晶相边界（MPB）。相变是由BCT含量高时的晶格畸变和氧空位引起的。通过XRD和TEM在RT-400°C下研究了原位相形成和畴结构依赖温度。观察到畴结构在200°C时由于成分波动而从室温下的铁电极性微区（PMR）变为弛豫极性纳米区（PNR），然后在400°C时变为顺电相。并在diff上通过XRD确认了结果Ť。 由于形成了MPB，在x = 0.075处获得了具有最高介电常数值的增强介电性能。 由于引入了BCT，在x = 0.075时观察到高残留极化值（Pr = 37 µC / cm ²）和低矫顽场（18 kV / cm）。在所有陶瓷的电流-电场行为（IE）回路中发现了四个峰值，证明存在电场感应的跃迁。