摘要
以柠檬酸和金属盐为原料,采用有机凝胶-热还原法制备了纳米晶Fe_(0.13)(Co_xNi_(1-x))_(0.87)(x=0.20,0.30,0.50, 0.80)微细纤维。采用FTIR,XRD和SEM等对纤维前驱体和热还原产物的结构、物相和形貌进行了分析;采用振动样品磁强计(VSM)对纤维的磁性进行了测试。结果表明:纤维直径分布在0.3—2μm之间,表面光滑,长径比大,组成纤维的晶粒尺寸约为34 nm。Fe_(0.13)(Co_xNi_(1-x))_(0.87)微细纤维表现出明显的磁各向异性,该性能主要受磁晶各向异性、形状各向异性和静磁相互作用等因素影响。纤维的易磁化方向为其轴向方向,难磁化方向为径向方向,所制备的Fe_(0.13)(Co_(0.50)Ni_(0.50))_(0.87)纤维的剩磁比M_r/M_s(剩余与饱和磁化强度比)最大,达到0.48。
Small diameter ferromagnetic metal fibers （Fe, Ni, Co and their alloys fibers） with the anisotropic characteristics are attractive as fillers in polymer-matrix composites, advanced electromagnetic interference （EMI） shielding and wide-band microwave absorbing materials. Because electromagnetic radiations with high frequencies only penetrate the near surface region of an electrical conductor, the composite material containing metal fibers with a small diameter is more effective than that with a large diameter. The filler of magnetic metal fibers with a diameter of 1 μm or less is therefore required technologically. Although iron fine fibers have been produced and used in several technological fields owing to a low cost, these iron fibers with a high specific surface area are generally not chemically stable due to easily oxidizing in an ambient atmosphere, which lowers their performance. The alloying can improve the anti-oxidation properties of ferromagnetic metal fibers and enhance their magnetic characteristics. In the present work, the nanocrystalline Fe0.13（CoxNi1-x）0.87 （x=0.20, 0.30, 0.50, 0.80） fine fibers were prepared by the organic-gel thermal reduction process using citric acid and metal salts as the raw materials. The structure and morphology of the gel precursors and the fibers derived from these gel precursors in the thermal reduction process were characterized by FTIR, XRD and SEM. The magnetic properties for as prepared alloy fibers were examined using vibrating sample magnetometer （VSM）. The diameters of alloy fibers are in the range of 0.3 to 2 #m and these consist of grains with the size of about 34 nm. The experimental data show that the aligned nanocrystalline Fe0.13（CoxNi1-x）0.87 fibers exhibit an obvious magnetic anisotropy. This magnetic anisotropy is mainly effeeted by the magnetocrystalline anisotropy, shape anisotropy and magnetostatic interaction. The magnetizing ease axis for the nanocrystalline fiber is parallel to the fiber axis whilst the hard axis is perpendicular to the fiber axis. The nanocrystalline Feo.la（Co0.50Ni0.50）0.87 fibers have a very high remanence ratio of 0.48.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第6期754-758,共5页
Acta Metallurgica Sinica
基金
国家自然科学基金项目50474038和50674048
中国博士后基金项目20080431069
江苏省无机及复合新材料重点实验室开放基金项目wjqfhxc1200602资助~~
