片状钛酸钡颗粒的熔盐法制备及其形貌

Molten-salt synthesis and morphology of plate-like barium titanate particles

为了得到有利于晶粒择优取向的片状钛酸钡形貌颗粒,采用合成出的片状模板原料,通过熔盐法制备了片状钛酸钡颗粒.首先,以碳酸钾、二氧化钛和钛酸锂为原料,在氯化钾熔盐中制备了具有类纤铁矿层状结构的钛酸盐(K0.8Ti1.73Li0.27O4).经酸交换后,得到了片状钛酸(H1.07Ti1.73O4,HTO)颗粒.HTO是一种具有层间通道结构和良好的离子交换性的片状模板,以HTO和碳酸钡为原料,氯化钠和氯化钾为熔盐,在820℃保温5h得到纯相的钛酸钡,其颗粒形貌呈现为宽5～8μm、长10～15μm,厚度约1μm左右的片状形貌,而且这些片状颗粒是由1μm的小片状颗粒按特定晶向排列而成.结果表明以HTO为模板的原位反应机制起了主要作用,产生保持了片状HTO模板形状的片状钛酸钡颗粒.该方法有望为制备织构化陶瓷提供良好各向异性钛酸钡粉体.

To obtain the plate-like morphology of the barium titanate particles which is beneficial to form preferably oriented grains,plate-like barium titanate particles were fabricated by molten salt method using a plate-like precursor.First,a layered titanate（K0.8Ti1.73Li0.27O4） with a lepidocrocite-like structure was synthesized with potassium carbonate,titanium dioxide and lithium carbonate in potassium chloride salt,which,after treatment in nitric acid solution,was subsequently transformed to H1.07Ti1.73O4（HTO） with the same layered structure and plate-like particle morphology.By using HTO and barium titanate as raw materials,sodium chloride and potassium chloride as mixed molten salt,plate-like barium titanate particles were synthesized at 820 ℃ for 5 h.The barium titanate platelets are 5-8 μm in width,10-15 μm in length,and about 1 μm in thickness,which consist of small flake particles（1 μm in size） arranged in a particular orientation to form a lamellar morphology.The results show that in-situ reaction with HTO as the template plays a dominant role in the formation of plate-like barium titanate particles.This approach is expected to provide good anisotropic barium titanate powders for the preparation of texture ceramic provides.