尖晶石型铁氧体纤维的制备及磁性能

Preparation and Magnetic Properties of Spinel-type Ferrite Fibres

以柠檬酸和金属盐为原料,采用有机凝胶-热分解法制备了MeFe_2O_4(Me=Zn,Ni_(0.5)Zn_(0.5),Ni_(0.4)Zn^(0.4)Cu_(0.2))铁氧体纤维.通过FT-IR、XRD、TG-DSC、SEM和VSM等测试技术对纤维前驱体凝胶的结构、热分解过程及热处理产物的物相、形貌以及纤维的磁性能等进行了表征.结果表明,在凝胶形成过程中,金属离子单齿或双齿螯合配位于柠檬酸根阴离子,形成线型分子结构,使凝胶有较好的可纺性.所制得的纤维具有较大的长径比,纤维直径在0.5～20.0μm之间.这些纤维在室温下都具有软磁特性,化学组成、晶粒大小及形貌对纤维的磁性能有着显著影响.ZnFe_2O_4、Ni_(0.5)Zn_(0.5)Fe_2O_4和Ni_(0.4)Zn_(0.4)Cu_(0.2)Fe_2O_4纤维的饱和磁化强度分别为2.6、12.7和40.0A·m^2·kg^(-1),相应的矫顽力分别为4.77、5.82和4.04kA·m^(-1).

The spinel-type MeFe2O4（Me=Zn,Ni0.5Zn0.5, Ni0.4Zn0.4Cu0.2） ferrite fibres with diameters of 0.5-20.0um and high aspect ratio （length/diameter） were successfully prepared by the organic gelthermal decomposition process using metal salts and citric acid as raw materials. The structure, thermal decomposition process and morphologies of the gel precursors and the fibres derived from thermal decomposition of these precursors were characterized by FT-IR, XRD, TG-DSC and SEM, and the electromagnetic performance of ferrite fibers were measured by VSM. The results show that linear-type structural molecules for the gel precursor is formed by a single dentate liganding type or bidentatechelating mode among citric acid and metal ions during the complexation reaction, and the gel composed of these linear-type molecules exhibits a good spinning performance. The MeFe2O4（Me=Zn, Ni0.5Zn0.5, Ni0.4Zn0.4Cu0.2） ferrite fibres all exhibit a soft magnetic performance, and chemical composition, grain size and morphology have considerable influence on the magnetic properties of these ferrite fibres. The saturation magnetization（Ms） of ZnFe2O4, Ni0.5Zn0.5Fe2O4 and Ni0.4Zn0.4Cu0.2Fe2O4 fibres are 2.6, 12.7 and 40.0A.m^2.kg^-1, and coercivity of these fibres correspondingly are 4.77, 5.82 and 4.04kA.m^-1, respectively.