微乳液法制备超细Ni-Fe复合物微粒

摘要

应用W/O型微乳液法制备了纳米量级超细铁-镍复合物微粒。X射线和透射、扫描电镜测试表明：它属于表面活性剂包裹型超细微粒。粒径＜30nm，密度2.89g/cm3的Ni-Fe微粒，比饱和磁化强度σs＝13～16Am2/kg，娇顽力Hc＝87～123 Oe，剩磁Br＝2.25～3.00Am2/kg，矫顽力较大，剩磁也较大，说明该超细复合微粒具有硬磁体的性质。X射线能谱分析表明，有部分Ni-Fe合金相形成。%Nanoparticles of Ni-Fe composite were prepared with the W/O microemulsion method. The investigations by XRD, IR and TEM show the ultrafine particles are coated by surfactants. Their average sizes are less than 30nm and their densities about 2.89g/cm3, the specific saturation magnetization σs＝13～16Am2/kg, the coercivity Hc＝87～123Oe and the residual magnetism Br＝2.25～3.00Ama/kg. The coercivity and residual magnetism are much higher, it is shown that the complex supermicropowders have hard magnetic properties. The analysis by X-ray energy spectroscopy shows that part of Ni-Fe has formed alloy phases. Magneticrheological (MR) effect of the MR fluid prepared from the ultrafine particles is superior and the subsidence stability of the MRF is excellent.