两种还原剂体系制备纳米镍粒子结构与磁性的对比

Structure and Characterization of Magnetic Nickel Nanoparticle by Different Reducing Agents

通过TEM及SEM表征粒子形态并对产物进行XRD分析，最后测定产物的磁化曲线。在微乳液环境中，NaBH4和N2H4-H2O两种还原体系得到粒子粒径分别为30-40nm和100nm，固体粉末产物未烧结时均呈无定形态，结晶性差。从磁化曲线可以看出，NaBH4还原制备的产物呈明显的铁磁性，饱和磁化强度（Ma）为32．28A·m^2·kg^-1，剩磁（M1）为10．98A·m^2·kg^-1，产物矫顽力为178kA·m^-1。而N2H4·H2O制备的产物几乎不呈现铁磁性，剩磁和矫顽力接近零。

Nickel nanoparticle was prepared in reverse microemulsion by two reducing agents （NaBH4 and N2H4·H2O ）. Transmission electron microscopy and scanning electronic microscopy were used to observe the morphology of particles. Then the powders of products were characterized by X-ray diffraction to study the structure. To characterize the magnetization of magnetic nanoparticle, the hysteretic magnetization loop was recorded at 5 K. The results show that products reduced by NaBH4 reducing agent present ferromagnetic properties, saturation magnetization is 32.28 A· m^2· kg^-1 and remanence is 10.98 A · m^2· kg^-1. However, the product shows coercivity as high as 178 kA·m^-1 while products reduced by N2H4·H2O reducing agent present no ferromagnetic properties, those remanence and coercivity are nearly zero.