中文摘要：

采用溶胶-凝胶法、水热法和溶胶-凝胶-水热法三种化学方法合成K0.5Bi0.5TiO3（KBT）无铅压电陶瓷粉体.用X射线衍射（XRD）分析产物的结构,用扫描电镜（SEM）和透射电镜（TEM）观察产物的形貌.实验结果表明,三种化学方法均可获得纯钙钛矿相KBT粉体,但不同工艺获得的粉体在形貌和生成机制上有很大的不同.溶胶-凝胶法属高温固相扩散机制,需要700℃以上温度煅烧才可获得KBT纯相,且粉体颗粒度大、团聚严重.水热法符合溶解-结晶机制,生长出四方形的KBT纳米片.溶胶-凝胶-水热法利用了凝胶团聚体空间链状结构的模板作用,通过原位结晶机制生长出KBT纳米线.

英文摘要：

Lead-free piezoelectric powders, Ko.sBio.sTiO3 （KBT）, were synthesized by sol-gel, hydrothermal and sol-gel-hydrothermal methods, respectively. The structures and morphologies of the powders were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results show that the pure perovskite KBT powders can be obtained by all three methods; however, the formation mechanism and morphology evolution of powders prepared by various processes are quite different. It was deduced that the solid diffusion mechanism was applied to sol-gel process. Due to the high-temperature treatment above 700 ℃, the KBT powders produced by sol-gel method had large size with serious agglomeration. The cubically shaped nanopowders were prepared by hydrothermal method, which belongs to dissolution-crystallization mechanism. The in-situ transformation mechanism was applied to sol-gel-hydrothermal process, and gel clusters played a crucial role in the formation of nanowire morphology.