Bismuth titanate based piezoceramics: Structural evolutions and electrical behaviors at different sintering temperatures

Highlights: • The lattice distortion is primarily determined by oxygen octahedral rotation. • A higher sintering temperature induces the larger domain size and fewer domain wall density. • The evolution of domains structure during depolarization process is revealed. -- Abstract: Bismuth titanate piezoceramics are considered as the most promising candidate for high temperature applications, and its multi-functional properties such as dielectricity, piezoelectricity, ferroelectricity, and so forth have been widely studied for several decades. Nevertheless, it still lacks of the systematically research on sintering temperature dependent electrical behaviors of bismuth titanate ceramics, and more importantly, to date there is no report on lattice distortion and domain evolution at different sintering temperatures for the ceramics as well, substantially bad for deep understanding the ceramics and limiting its further applications. Here, a type of bismuth titanate based ceramics (Bi_3.96Ce_0.04Ti_2.97W_0.015Nb_0.015O₁₂, abbreviated as BCTWN) was prepared by traditional solid-phase reaction technology, and the effects of sintering temperature on the multiple microstructures and electrical properties for BCTWN ceramics were investigated in details. The results show that oxygen octahedral rotation primarily determines the lattice distortion of pseudo-perovskite layer, and domain structures are composed of 90° and 180° domains. The higher sintering temperature generates more distorted crystal structure and induces larger domain size and fewer domain wall density. The grain features and defect dipole distribution are also significantly affected by sintering temperature, thus yielding the distinct electrical behaviors. This research sheds insight in micro-mechanism of optimizing electrical properties, and contributes to expanding more applications for bismuth titanate ferroelectrics.