Simple chemical route for the quantitative precipitation of barium–strontium titanyl oxalate precursor leading to Ba1−xSrxTiO3 powders
Simple chemical route for the quantitative precipitation of barium–strontium titanyl oxalate precursor leading to Ba1−xSrxTiO3 powders
复制标题
DOI：
10.1016/s0167-577x(02)01091-1
复制
发表时间：
2003-04
影响因子：
3
通讯作者：
Y. Khollam;S. Bhoraskar;S. B. Deshpande;H. S. Potdar;N. Pavaskar;S. Sainkar;S. Date
中科院分区：
文献类型：
--
作者：
Y. Khollam;S. Bhoraskar;S. B. Deshpande;H. S. Potdar;N. Pavaskar;S. Sainkar;S. Date
利用草酸钛（HTO）[H2 TiO（C2 O 4）2·2 H2O]、氢氧化钡和硝酸锶在室温下的简单化学交换反应，成功地制备了草酸钛氧钡锶（Ba 1 −xSrxTiO（C2 O 4）2·4 H2O，x=0.25）前驱体粉末。最初，通过使用0.1M四丁氧基钛和0.2M草酸在异丙醇（IPA）中的反应制备草酰钛酸。将氢氧化钡和硝酸锶以化学计量的量直接加入到该溶液中。仅在逐滴添加蒸馏水之后实现的所需溶解度导致BSTO分子前体的受控沉淀。为了保持平衡（pH条件），越来越多的Ba（OH）2和Sr（NO3）2固体溶解，反应继续进行。交换反应的动力学由水的加入速率决定。BSTO在空气中于750 °C/4 h热解产生Ba 1 − xSrxTiO 3（BST）粉末。采用微量分析、化学分析、DTA/TGA、XRD、IR、SEM等手段对BST粉体进行了表征，结果表明：BST粉体为立方晶系、化学计量比、纯度高、产率>99%、团聚性好（粒径为0.5 ~ 2 μm）。
Barium–strontium titanyl oxalate (BSTO) [Ba1−xSrxTiO(C2O4)2·4H2O with x=0.25 precursor powders] were prepared successfully by using the simple chemical exchange reaction between oxalotitanic acid (HTO) [H2TiO(C2O4)2·2H2O], barium hydroxide and strontium nitrate at room temperature. Initially, oxalotitanic acid was prepared by using the reaction between 0.1 M titanium tetrabutoxide and 0.2 M oxalic acid in isopropanol (IPA). Barium hydroxide and strontium nitrate were added directly to this solution in stoichiometric amounts. The required solubility achieved only after addition of distilled water dropwise leads to the controlled precipitation of BSTO molecular precursor. To maintain the equilibrium (pH conditions), more and more Ba(OH)2and Sr(NO3)2solids get dissolved and reaction continues. The kinetics of exchange reaction is governed by the rate of addition of water. The pyrolysis of BSTO at 750 °C/4 h in air produced the Ba1−xSrxTiO3(BST) powders. The characterization studies were carried on the as-dried and calcined powders by various physicochemical techniques viz. microanalysis, chemical analysis, DTA/TGA, XRD, IR, scanning electron microscopy (SEM), etc. It revealed that the BST powders are cubic, stoichiometric, highly pure with yield>99% and agglomerated nature (size: 0.5–2 μm).