Molten-Salt Synthesis of Bismuth Titanate and Fabrication of PbTiO3-based Textured Ceramics

Grain-oriented ceramics, in which the grains are aligned around a preferred crystallographic axis, are of interest for increasing the figure of merit of piezoelectric ceramics. Templated grain growth (TGG), in which a fine matrix is recrystallised upon oriented seed crystals, is one of the more successful techniques for preparing ceramics with such crystallographic texture. Seeds are usually required to exhibit shape anisotropy in a defined orientation with an appropriate crystallographic template plane. In this study, Bi₄Ti₃O₁₂ (BiT) seeds were produced via molten-salt synthesis. The effect of temperature and dwelling time on the morphology and structure of Bi₄Ti₃O₁₂ powders was studied, in order to identify the optimum conditions for seed preparation. The chosen Bi₄Ti₃O₁₂ seeds were then added to PbTiO₃-based matrices (Bi_0.5Fe_0.5Pb_0.47La_0.03Ti_0.5O_3+x) to produce Bi₄Ti₃O₁₂ oriented BFPT ceramics by tape casting. The microstructure and the calculated orientation factors of the textured ceramics are reported.