铋层状共生化合物Bi_7Ti_4NbO_(21)亚结构层Bi_4Ti_3O_(12)中Nb的固溶(英文)  

Nb Solution within Bi_4Ti_3O_(12) Sub-structure in the Intergrowth Bismuth-layered Compound Bi_7Ti_4NbO_(21)

作　　者：高翔 王贤浩[1] 邢娟娟[1] 顾辉[1] 张发强[2,3] 李永祥[2] 

机构地区：[1]中国科学院上海硅酸盐研究所,高性能陶瓷与超微结构国家重点实验室,上海200050 [2]中国科学院上海硅酸盐研究所,信息功能材料与器件研究中心,上海200050 [3]中国科学院大学,北京100039

出　　处：《无机材料学报》2013年第5期561-565,共5页Journal of Inorganic Materials

基　　金：National Natural Science Foundation of China(50932007);National Basic Research Program of China(973 Program)(2009CB613305)

摘　　要：采用常规高分辨透射电镜(HRTEM)在层状共生化合物Bi7Ti4NbO21中可经常观察到大量生长缺陷:比如插入额外的Bi3TiNbO9或Bi4Ti3O12层而产生的无序共生结构,以及由共生相Bi7Ti4NbO21和母相Bi4Ti3O12在同一晶粒内形成的共相体[1]。为了给先前提出的共生结构重组生长模型提供更充分的依据,采用低/中分辨率下的高角环暗场像(HAADF)配合X射线能谱(EDXS)定量分析来研究共生缺陷的产生原因。观察到一种共生缺陷可以从共生相到Bi4Ti3O12母相发生结构渐变。用空间分辨的能谱测量可以排除相邻Bi3TiNbO9层所带来的干扰,其结果表明Bi4Ti3O12层中固溶了相当含量的Nb。一定量Nb的固溶进一步表明,在形成共生结构的过程中两种亚结构层之间发生了普遍的阳离子互换过程,而这一过程应该通过重组模型中的部分溶解液相来实现[1]。In intergrowth bismuth-layered compound BivTi4NbO2, growth defects, such as disordered intergrowth with extra layers of BiaTi3012 or Bi3NbTiO9 constituent sub-structures, or as the co-growth of Bi7TiaNbO21 onto BiaTi3012 grains, were frequently observed using high-resolution transmission electron microscope （HRTEM）. In order to further find evidence to support the re-ordering picture that was proposed to explain formation of the intergrowth and associated defects, we employ the low- and medium-resolution high-angle annular-dark-field （HAADF） imaging combined with the quantitative energy dispersive X-ray spectroscope （EDXS） analysis to probe into a heavily defected intergrowth structure. A gradual transformation from the ordered intergrowth of both sub-structures to the dominance of BiaTi3012 sub-structure was observed. A substantial level of Nb solution could be detected in n-layered （n 92） BinTi3Ol2 sub-structure by spatially-resolved compositional quantification to differentiate the contribution from the adjacent single Bi3NbTiO9 layer. The presence of a finite Nb concentration in the Bi4Ti3012 sub-structure indicates a substantial and uniform cations inter-change occurred between the two sub-structures, which is inherited most likely from the parent phases via the partially dissolved sintering melts.

关 键 词：层状铁电体 固溶 HAADF 烧结机制 

分 类 号：TQ174[化学工程—陶瓷工业]