有机凝胶前驱体转化法制备CoFe_2O_4–BaTiO_3纳米复合纤维

PREPARATION OF CoFe_2O_4–BaTiO_3 NANO-COMPOSITE FIBERS BY ORGANIC GEL-THERMAL DECOMPOSITION PROCESS

铁磁–铁电复合纤维是一种新型功能陶瓷纤维材料,可潜在地用于磁、电能量转换。以柠檬酸和金属盐为原料,采用有机凝胶前驱体转化法制备了xCoFe2O4–(1–x)BaTiO3(x=0.2,0.3,0.4,0.5)纳米复合纤维。利用红外光谱、热重–差热分析、X射线衍射、扫描电子显微镜和振动样品磁强计等对纤维前驱体凝胶的结构、热分解过程及热处理产物组成、形貌和磁性能进行表征。研究表明:所制得的复合纤维直径细小、均匀、致密,最小直径达到1μm,长径比可达1×105。随着焙烧温度从900℃升高到1180℃,复合纤维中BaTiO3和CoFe2O4平均晶粒尺寸为20～70nm。xCoFe2O4–(1–x)BaTiO3纳米复合纤维的饱和磁化强度Ms与CoFe2O4在复合纤维中所占的摩尔分数x之间存在线性关系。

The magnetoelectric composites of ferrite and ferroelectric phases are a new type of functional ceramic material and will be used in many fields of magnetoelectric energy conversion, xCoFe2O4-（1-x）BaTiO3（x=0.2, 0.3, 0.4, 0.5） nano-composite fibers were prepared by the organic gel-thermal decomposition process from the raw materials of citric acid and metal salts. The structure, thermal decomposition process and morphologies of the gel precursors and the fibers derived from thermal decomposition of the gel precursors were characterized by Fourier transform infrared spectroscopy, thermogravimetric-differential thermal analysis, X-ray diffraction and scanning electron microscope. The magnetic properties of the xCoFe2O4-（1-x）BaTiO3 fibers were measured by vibrating sample magnetometer. The results show that the xCoFe204-（1-x）BaTiO3 nano-composite fibers as prepared have diameters as thin as 1μm, a high aspect ratio up to 1×10^5, and a dense surface. The average grain sizes of BaTiO3 and CoFe2O4 in the composite fibers increase correspondingly from 20 to 70 nm with the increasing calcination temperatures from 900 to 1180℃. The saturation magnetization of the CoFe2O4-BaTiO3 nano-composite fibers exhibits a linear relationship with the mole fraction of CoFe2O4 in the composites.