PDF《熔盐合成技术制备片状（Sr, Ba）TiO3 晶粒》

第 卷第 期 中国有色金属学报 年月17

6 2007

6 Vol.

17 No.6 The Chinese Journal of Nonferrous Metals Jun.

2007 文章编号:1004-0609(2007)06-0871-07 熔盐合成技术制备片状(Sr, Ba)TiO3 晶粒 张晓泳,周科朝,李志友,侯俊峰 (中南大学 粉末冶金国家重点实验室,长沙 410083) 摘要:以KCl 为助熔剂,采用熔盐合成技术制备片状(Sr, Ba)TiO3 晶粒,研究不同前驱体及反应方式对产物相组 成和形貌的影响.结果表明:BaO 与片状 SrTiO3 反应可获得以(Sr, Ba)TiO3 为主相的产物,产物相在 SrTiO3 表面 无规则析出且非取向长大,经烧结后形成片状多晶团聚体;

片状 Sr3Ti2O7 与BaO 和TiO2 反应所得产物也以(Sr, Ba)TiO3 为主,同时生成少量(Sr, Ba)3Ti2O7 相,产物中除片状(Sr, Ba)TiO3 晶粒外,还通过 Sr2+ 置换由 BaO 与TiO2 反应所得块状 BaTiO3 晶粒中的 Ba2+ 、以及反应物溶解?反应?析出生成许多块状和无规则状小晶粒;

对于两步合 成工艺,Sr3Ti2O7 先与 BaO 反应可得到片状(Sr, Ba)3Ti2O7,与TiO2 二次反应后得到片状(Sr, Ba)TiO3 晶粒;

由于此 方式没有生成块状 BaTiO3 这一过程,产物中非片状晶粒数量大幅度减少. 关键词:(Sr, Ba)TiO3;

片状晶粒;

熔盐合成 中图分类号:TM

28 文献标识码:A Synthesis of tabular (Sr, Ba)TiO3 crystals by molten salt method ZHANG Xiao-yong, ZHOU Ke-chao, LI Zhi-you, HOU Jun-feng (State Key laboratory of Powder Metallurgy, Central South University, Changsha 410083, China) Abstract: The tabular (Sr, Ba)TiO3 particles were prepared in KCl flux by molten salt synthesis. The effects of precursors and reactive modes on the phase composition and morphology of products were investigated. The results show that the product with main phase (Sr, Ba)TiO3 is obtained by reacting SrTiO3 with BaO. The tabular aggregates are formed by sintering irregular grains that precipitate grow arbitrarily on the SrTiO3 surfaces. (Sr, Ba)TiO3 is also the main phase by reacting tabular Sr3Ti2O7 with BaO and TiO2. Besides the tabular (Sr, Ba)TiO3 particles, many small non-tabular particles are generated from the substituting of Sr2+ for Ba2+ in BaTiO3 formed by reacting BaO with TiO2, or the dissolving-reacting-precipitating process. For two-step process, tabular (Sr, Ba)3Ti2O7 particles are obtained by reacting Sr3Ti2O7 with BaO, which further react with TiO2 to form tabular (Sr, Ba)TiO3 particles. Because no BaTiO3 generates, the amount of small non-tabular particles decreases greatly. Key words: (Sr, Ba)TiO3;

tabular template;

molten salt synthesis 织构型多晶压电陶瓷由于具有与相应单晶相近的 优良压电性能,但其制备工艺比后者简单且受到越来 越多的关注和重视,并成为近年来压电陶瓷方面的研 究热点[1?4] . 多晶织构材料的制备主要采用模板晶粒生 长技术(Template grain growth,TGG)[4?9] ,此工艺流程 为:首先将低维尺度模板按其晶体取向定向排列于基 体粉末中,在高温下基体细小晶粒在模板上重新定向 形核、生长,最终形成多晶织构.模板的材料体系选 择及形貌特征在 TGG 技术中非常关键,一般需满足 以下几个要求[4?5, 9?10] : 1) 晶体结构与基体材料相同或 相似且晶格匹配良好;

2) 形貌各向异性程度大;

3) 几 何尺寸大于基体晶粒;

4) 晶体取向与基体具有最优压 电性能的晶向一致;

5) 高温热稳定性良好. SrTiO3 [5] 和BaTiO3 [9] 模板已被用于制备 Pb(Mg1/3- 基金项目:国家自然科学基金资助项目(50002015) 收稿日期:2006-10-13;