BaTiO_3凝胶合成的红外吸收光谱研究

Studies of Infrared Absorption Spectra on Synthesizing of BaTiO_3 Gel

以丁醇钛和醋酸钡为原材料,醋酸为化学添加剂,用溶胶-凝胶方法制备成凝胶,经过700℃热处理后,得到具有四方钙钛矿结构的 BaTiO_3结晶氧化物。红外吸收光谱分析表明,醋酸不仅作为催化剂,而且也作为配位取代物起作用;醋酸根二配位取代丁醇钛中的氧丁基,并直接与钛键合,改变了金属醇盐原材料的性质,从而改变了水解和聚合的速率。由于在凝胶中醋酸钡仍然存在,因此设想钡与钛是通过醋酸根连接并相互作用。控制醋酸加入量,可得到适合的水解和聚合的相对速率,从而使钡与钛能有机会通过醋酸根连接,由此得到透明、均匀并且不易碎裂的凝胶。

BaTiO_3 gel was synthesized by a sol-gel method from titanium butoxide and ba-rium acetate as precursors and acetic acid as a chemical additive.BaTiO_3 crystallineoxide with tetragonal perovskite structure was obtained after heat treatment of thegel at 700℃.The results of infrared absorption spectra show that the acetic acidacts not only as a catalyst,but also as a dentate replacement,bi-dentate acetate re-places the OR group of titanium butoxide and is directly bound to titanium,there-fore the behaviour of the titanium butoxide is modified,and the velocity of hydro-lysis and polymerization is modified too.It is suggested that Ba and Ti be connec-ted and interacted by the acetic ligands according to barium acetate existing in theBaTiO_3 gel.while a proper amount of acetic acid is added,a suitable relative velo-sity of the hydrolysis and the polymerization can be obtained,so that Ba and Timay have a chance to connect each other by the acetic ligands,and the gel Withbetter quality can be obtained.