通过熔盐法制备出具有铋层结构的前驱体Na0.5Bi4.5Ti4O15,其取向度f值(Lotgering factor法)高达0.9。粉体Na0.5Bi4.5Ti4O15再与Na2CO3和TiO2发生拓扑化学反应,铋层状结构Na0.5Bi4.5Ti4O15完全转变成钙钛矿结构的Na0.5Bi0.5TiO3(NBT),所得到NBT粉体保留了NBIT的层状形貌,其厚度约0.4μm,长度为5~10μm,显示出较高的各向异性。研究了烧成温度对前躯体NBIT微粒形态的影响。通过SEM分析,固相法,熔盐法和拓扑反应合成的NBT粉体微观结构显示出巨大的差异。
As the precursors of Na0.5Bi0.5TiO3 (NBT), bismuth-layer-structured Na0.5Bi4.5Ti4O15 (NBIT)particles were first synthesized by molten salt process. The degree of orientation (calculated by Lotgering factor method ) f is 0.9. After the topochemical reaction with the complementary reactants (Na2CO3 and TiO2) in NKCI flux, layer-structured NBIT particles were transformed to the perovskite NBT particles retaining the morphology feature of the precursor. NBT particles with a thickness of about 0.4μm and a length of 5-10μm. It showed highly anisotropic structure. The effects of NBIT particles reacting temperature on the morphology were investigated. The microstructure of NBT particles synthesized by solid-state reaction,molten salt method and topochemical reaction showed notable difference.