四方相钙钛矿PbTiO3的水热合成及机理研究

Synthesis and Mechanism of Tetragonal Perovskite Structure PbTiO_3 by a Hydrothermal Route

以自制氢氧化铅和二氧化钛作为原料,在溶液pH≈13-14,180℃的条件下添加合适的矿化剂反应24 h,采用水热法制备出了颗粒均匀（边长≈500 nm）的四方相钙钛矿PbTiO3（PT）纳米立方体,并利用XRD,SEM,TEM等分析手段对样品的结构和形貌进行了表征,并对其主要影响因素：前驱物的种类、溶液的pH值、物料的摩尔配比及反应时间等进行了研究,同时提出了可能的形成机理,即＂溶解—醇解—晶体生长—再结晶＂机理.

Lead titanate （PbTiO3, PT） crystals are synthesized from the raw materials, namely self-made Pb（OH）2 and the purchased TiO2, by a hydrothermal route, in which the precursors are heated to 180℃ with durations for 24h at pH= 13- 14. The homogeneous PbTiO3 crystals with tetragonal perovskite structure are obtained through the synthesis route. The products are characterized by X-Ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The influences of the kinds of the precursors and basicity, the Pb/Ti ratio, the KOH concentration, and the reaction time on the morphology and microstructure of PbTiO3 crystals are investigated. By surveying the variations of the crystal micrographs, the possible formation mechanism can he proposed as dissolution-alcoholysis-crystal growth-recrystallization.