溶剂热可控合成亚微米Co粉及其磁性能

Size-controllable synthesis of cobalt submicrospheres by solvothermal method and their magnetic properties

采用溶剂热液相还原的方法可控合成粒径分布窄的球形Co粉.用X线衍射仪（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）及超导量子干涉仪磁强计（SQUID）表征合成Co粉的物相、形貌、粒度和磁性能.结果表明：所制备的样品为六方相金属Co单质,其分散性好,粒径分布窄;Co粉的粒径可通过调节NaOH的用量在0.68～ 6.2μm有效调控.通过合成机制的分析,认为体系中Co2＋首先生成纳米片状的Co盐前驱体,而游离Co粒子与乙二胺配位并被还原成Co粉.由于前驱体能够降低游离Co2＋的浓度并缓慢释放Co源,使得Co粉具有较窄的粒径分布,且制得的Co粉皆具有较好的磁性能.

Cobalt submicrospheres with narrow particle size distribution were synthesized by a solvothermal solution reduction method.The obtained products were characterized by X-ray diffraction （XRD）,scanning electron microscopy （SEM）,transmission electron microscopy （TEM）,and superconducting quantum interference device magnetometer （SQUID）.Results showed that well-dispersed cobalt submicrospheres of hexagonal structure were successfully synthesized.The powders possessed narrow particle size distribution,and the size could be well controlled in the range of 0.68-6.2 μm by controlling the amount of NaOH.The growth mechanism based on time-dependent experiments revealed that cobalt ions first to nanosheet precursor,and other dissociative cobalt ions were coordinated with ethanediamine and reduced to cobalt powder.The formation of precursor could give a sharp reduction of dissociative cobalt ions and provide a controlled release of cobalt ion,which facilitated the preparation of cobalt with narrow particle size distribution.The obtained products had well magnetic properties.