钴纳米颗粒的制备及其表征

Synthesis and Characterization of Cobalt Nanoparticles

采用简单的溶液还原方法,以聚乙烯吡咯烷酮(PVP,MW=58,000)作为高分子表面修饰剂,用水合肼(50%)作为还原剂。经回流处理,成功地制备出了分散性较好的钴纳米颗粒。利用XRD、TEM、SQUID等实验方法对产物的形貌、物相及磁性进行了表征。结果表明,产物为六方结构。其饱和磁化强度为153 emu/g,～1.62μB/Co,是体相材料的饱和磁矩的95%,其矫顽力为5174 A·m^(-1)。此方法的优点在于反应条件温和、成本较低,重复性强、产率高且宜于控制。

Well-dispersed Co nanoparticles were synthesized successfully by using simple solution reduction method. In this reaction system, PVP serves as surface modified reagent, and hydrazine plays as reduced reagent. The products were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and superconducting quantum interference device （SQUID） system. The results show that the product was h-Co nanostructure. The saturation magnetization determined at high field is about 153 emu/g, which is roughly 1.62 μB/Co. This amounts to 95% of the bulk value, -1.72 μB/Co, which has a coercivity of-65 Oeat 300 K. The advantages of the method are mild, low-cost, well-repeatable, high-yield and easily controllable