Hydrothermal / Solvothermal Synthesis Of Ni And Co Magnetic Nanoparticles

In this paper, Ni and Co magnetic powders with various morphologies were controllably fabricated by simple hydrothermal and solvothermal methods. The paper includes two parts. In the first part, the flower-like nickel microstructures with uniformly monodisperse morphology were prepared by means of a facile solvothermal method with deionized water and ethylene glycol as mixed solvents under different experimental conditions. In the second part, using nickel acetate as cobalt sources, chain-like cobalt microstructures with uniformly monodisperse morphology were prepared by means of a facile solvothermal method with deionized water and ethylene glycol as mixed solvents. The structure, morphology, and magnetic properties of the reaction products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM), respectively. The results showed that the products were face-centered cubic (fcc) Ni and Hexagonal (hcp) cobalt respectively. The morphology of Ni was flower-like structure, the morphology of Co was chain-like structure. The average diameter of each flower was about 2～5μm and average diameter of each particle was about 2μm. The influences of preparation conditions on the morphology of products were also investigated. It can be seen that the amount of NaOH plays a great role in the morphology of Ni microstructures, but there is no obvious effects on the morphology of Co microstructures. It is necessary to using mixed solvent for obtaining flower-like nickel microstructures and chain-like cobalt microstructures. We can't obtain flower-like nickel microstructures and chain-like cobalt microstructures without using water. While the volume ratio of hydrazine hydrate to ethylene glycol was changed in some range, the flower-like nickel microstructures and chain-like cobalt microstructures can be obtained.