The fabrication and magnetic properties of Ni fibers synthesized under external magnetic fields
The fabrication and magnetic properties of Ni fibers synthesized under external magnetic fields
复制标题
DOI：
10.1002/ejic.200800200
复制
发表时间：
2008-06-01
影响因子：
2.3
通讯作者：
Zhang, Zhijun
中科院分区：
文献类型：
--
作者：
Gong, Chunhong;Yu, Laigui;Zhang, Zhijun
在外加磁场的作用下，用水合肼还原Ni 2+离子，制备了不同长度的一维纳米晶Ni纤维。采用扫描电镜（SEM）、X射线衍射（XRD）和室温磁滞回线测试等手段，系统研究了反应条件和磁场强度对Ni纤维微观结构和磁性能的影响。研究发现，外磁场强度和镍盐溶液浓度对镍纤维的微观结构和磁性能起着关键作用。也就是说，Ni纤维的平均长度随着Ni 2+离子浓度和外磁场强度的增加而显著增加。此外，外磁场下制备的镍纤维样品具有更高的矩形度和双折射率值比在没有外磁场下合成的。因此，选择相对高的外磁场强度和Ni 2+离子浓度来制备具有改善的微观结构和磁性能的期望的Ni纤维。该方法具有反应速度快、成本低的优点，有望实现磁性材料形貌和磁性能的有效控制以及大规模生产。所得镍纤维可能是潜在的催化剂，磁存储材料，和用于屏蔽电磁干扰（EMI）的导电填料。((C)Wiley-VCH Verlag GmbH & Co. KGaA，69451魏因海姆，德国，2008）。
One-dimensional (1D) nanocrystallites Ni fibers with different lengths were fabricated by the reduction of Ni2+ ions by hydrazine hydrate in the presence of external magnetic fields. The effect of the reaction conditions and magnetic field intensity on the microstructures and magnetic properties of the Ni fibers were systematically investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and measurement of hysteresis loops at room temperature. It was found that both the intensity of the external magnetic field and the concentration of the nickel salt solution played key roles in governing the microstructures and magnetic properties of the Ni fibers. Namely, the mean length of the Ni fibers increased markedly with increasing Ni2+ ion concentration and intensity of the external magnetic field as well. Moreover, the Ni fiber samples prepared under external magnetic fields had higher squareness and coercivity values than those synthesized in the absence of the external magnetic field. Therefore, a relatively high intensity of the external magnetic field and concentration of the Ni2+ ions was selected for the preparation of the desired Ni fibers with improved microstructures and magnetic properties. The present approach has the advantages of having a fast reaction rate and low cost and might be promising for the effective control of the shape and magnetic properties of magnetic materials and for large-scale production as well. The resulting Ni fibers might be potential catalysts, magnetic storage materials, and conductive fillers for shielding of electromagnetic interference (EMI). ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).