熔盐合成技术制备片状(Sr,Ba)TiO3晶粒

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Sr^2＋置换由BaO与TiO2反应所得块状BaTiO3晶粒中的Ba^2＋、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。

Synthesis of tabular (Sr, Ba)TiO3 crystals by molten salt method

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.