SYNTHESIS OF ANISOTROPIC LEAD TITANATE POWDERS FOR TEMPLATED GRAIN GROWTH OF TEXTURED PIEZOELECTRIC CERAMICS

摘要

Needle-shaped PbTiO_3 (PT) template particles were successfully synthesized using two different types of approaches, molten salt synthesis (MSS) and thermal synthesis method. In eutectic NaCl–KCl molten salt system, homogeneous and nonagglomerated needle-shaped PT particles were produced from PbO and needle-like TiO_2 compound heated at 800–850℃ for 2h. The effect of heating temperature on the morphology of formed powders was studied in order to identify the optimum processing parameters. The template formation mechanism is discussed. Using thermal synthesis method, comparable needle-shaped PT crystalline particles were also obtained in one step. Plate-shaped PT powders were derived via flux synthesis. The effect of additives such as MnCl_2 and LiF on the morphology of derived PT was studied. Adding a certain amount of MnCl_2 led to the formation of well-defined plate-shaped PT particles. The structure and morphology of synthesized powders were characterized by means of X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM).