水热条件下BaTiO3晶粒中OH^—缺陷的形成

Formation of OH - Defect in BaTiO 3 Crystallite under Hydrothermal Conditions

本文研究了水热条件下制备的ＢａＴｉＯ３晶粒中ＯＨ－缺陷的形成。实验表明，随着溶液中的钡钛摩尔比增大，产物中的ＯＨ－缺陷减少，四方相ＢａＴｉＯ３的含量增多。从结晶化学的角度剖析了ＢａＴｉＯ３与锐钛矿结构的相似性，两种晶粒中的Ｔｉ—Ｏ６八面体的结晶方位一致，其顶角分别指向晶轴ａ，ｂ和ｃ，因此锐钛矿的生长基元可以往ＢａＴｉＯ３晶粒上配向生长，在结构失配处即可形成缺陷，在缺陷部分ＴｉＯ６八面体自由端处保留了ＯＨ－结构，这是形成晶粒中ＯＨ－缺陷的主要原因。

The formation of OH - defect in BaTiO 3 crystallite has been studied.It has been found that OH - defect concentration decrease and content of tetragonal BaTiO 3 in product increase with increasing of Ba /Ti molar ratio in solution.The structure similarity between BaTiO 3 and anatase has been discussed on the crystal chemistry viewpoint.The crystallization orientation of TiO 6 octahedra in these two crystals are both point to the crystal axis a,b and c .Thus the growth units of anatase can epitaxially grow on BaTiO 3 crystallites.The defects are formed when the structure mismatch ocurred,the defects are the free end of TiO 6 octahedron,i.e.OH -.The structure mismatch is the major cause for the formation of OH - defects in the crystallites.