Processing-controlled texture development in Li/Nb co-doped BNT-based ceramics

초록

The soaking time in sintering governs densification kinetics, grain growth, and orientation preservation of template particles, thereby directly influencing the degree of texture and corresponding functional properties. This work reports 0.95[(Bi0.5Na0.49Li0.01)Ti0.99Nb0.01O3]–0.05BaZrO3 (BNLTN–BZ) textured ceramics developed by a reactive templated grain growth (RTGG) method combined with a tape casting process. Texture development was realized by incorporating 5 wt% (Bi0.5Na0.5)TiO3 (BNT) template particles synthesized via a topochemical microcrystal conversion (TMC) route. The influence of soaking time in sintering on grain orientation, microstructural evolution, crystalline phase, dielectric behavior, piezoelectric, and energy storage performance was investigated systematically. X-ray diffraction analysis confirmed the formation of a single-phase perovskite structure in all samples, with no detectable secondary phases. Extending the soaking time in sintering resulted in a progressive enhancement of the grain orientation factor and promoted a denser, well-aligned microstructure. With prolonged thermal treatment, the room-temperature dielectric permittivity increased, whereas the depolarization temperature exhibited a gradual shift towards lower temperatures. A moderate energy storage density of 0.80 J/cm3 under an applied electric field of 80 kV/cm was achieved for the sample sintered with a 15 h soaking time. Moreover, a large electric-field-induced strain of approximately 0.40%, corresponding to a dynamic piezoelectric coefficient (d33*) of 533 pm/V, was obtained under an applied field of 75 kV/cm. These results demonstrate that careful control of the soaking time in sintering is a key parameter for tailoring the texture and electromechanical performance of RTGG-derived Bi-based textured piezoceramics, highlighting their potential for high-performance actuator applications.

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