2019 年 127 巻 6 号 p. 362-368
Layered titanate H1.08Ti1.73O4·nH2O (HTO) particles with plate-like morphology were used as a template for the fabrication of grain-oriented bismuth potassium titanate [(Bi0.5K0.5)TiO3, or BKT] ceramics by a reactive-templated grain growth method. Single perovskite-phase textured BKT ceramics were successfully fabricated with optimizing the preparation conditions such as mixing procedure of matrix and template particles with a binder solution, temperature programs for binder removal and sintering, and sintering conditions. Microstructure evaluation suggested that the sintering with or without weight-pressing and a temperature program used could significantly affect the degree of texture development. The debinding and sintering with weight-pressing helped on the proper alignment of oriented particles and/or grains along with promoting the growth of the oriented plate-like BKT particles, formed by an in situ topotactic transformation reaction of plate-like HTO templates, resulting in a high degree of orientation. Using optimum preparation conditions, single perovskite-phase BKT ceramics with grain-orientation over 85% were successfully fabricated for the first time via a conventional sintering method.
