物理化学学报2011，Vol.27Issue(5)：1254-1260,7.
均匀共沉淀法制备钛酸钡-钡铁氧体核-壳结构粒子
Preparation of BaTiO3-BaFe12O19 Core-Shell Structure Particles by Homogeneous Coprecipitation
摘要
Abstract
BaTiO3-BaFe12O19 core-shell structure particles were obtained using the homogeneous coprecipitation method.The effects of temperature, molar ratio of urea to metal ions (R), and BaTiO3 concentration on the morphology and structure of the core-shell particles were investigated.The mechanism of formation for the BaTiO3-BaFe12O19 core-shell structure particles and their magnetic property were also discussed.Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to characterize the morphology and structure of the BaTiO3-BaFe12O19 precursor core-shell structure particles and the BaTiO3-BaFe12O19 core-shell structure particles.A vibrating sample magnetometer (VSM) was used to characterize the magnetic property.The results indicated that the obtained sample possessed an integrated and smooth shell of about 10 nm in size and the metal ions precipitated completely after homogeneous coprecipitation when the sample was synthesized under the following conditions: 100 ℃,R=180, and a BaTiO3 concentration of 2.5 g·L-1.A large amount of free particle impurities appeared if the temperature and R value were too high.The shell thickness of the BaTiO3-BaFe12O19 precursor core-shell structure particles tended to decrease as the BaTiO3 concentration increased.The BaFe12O19 phase in the shell began to form when the calcination temperature reached 900 ℃.The mechanism of formation included the formation of BaFe2O4 by the reaction of crystalline α-Fe2O3 and BaCO3 initially, and this was followed by the reaction of BaFe2O4 and α-Fe2O3 to form the final BaFe12O19.As the temperature increased to 1000 ℃, a complete BaFe12O19 shell was obtained.The saturation magnetization and coercivity of the BaTiO3-BaFe12O19 core-shell structure particles increased and decreased from 16.5 to 39.5 A·m2·kg-1 and from 340 to 316 kA·m-1, respectively, as the calcination temperature increased from 900 to 1000 ℃.关键词
均匀共沉淀/核-壳粒子/钛酸钡/钡铁氧体Key words
Homogeneous coprecipitation/ Core-shell particles/ BaTiO3/ BaFe12O19分类
化学化工引用本文复制引用
刘建华,游盾,于美,李松梅..均匀共沉淀法制备钛酸钡-钡铁氧体核-壳结构粒子[J].物理化学学报,2011,27(5):1254-1260,7.基金项目
国家自然科学基金(51001007)资助项目 （51001007）
