Influence of the Co:Ni Ratio on the Properties of Co-Ni Nanoparticles and Their Carbon-containing Nanocomposites

摘要

Co-Ni nanoparticles are synthesized through a chemical borohydride reduction with 0.2M NaBH₄ in a mixture of water solutions of the chloride salts (0.1M CoCl₂ · 6H₂O and 0.1M NiCl₂ · 6H₂O) at a different Co: Ni ratio at room temperature in open lab space. Template synthesis of the same nanoparticles is carried out using graphite as a support in the presence of β-cyclodextin yielding carbon-containing nanocomposites. In the both cases of the synthesis it is experimented three ratios of Co: Ni=1:1, 4:1, and 1:4 to study the properties of these nanomaterials in connection with the influence of the different Co and Ni content. The morphology, the elemental, and phase composition are investigated by the help of Scanning electron microscopy (SEM), Energy dispersitive spectroscopy (EDS) and X-ray diffraction (XRD) analyses, respectively. Magnetic properties are also examined by the Vibrating Sample Magnetometer (VSM) at room temperature. In the all cases the particle morphology presents assemblies in size from 0.5 to 100 μm formed by nanopartilces due to the unsaturated nanosurface and magnetic forces. The Co-Ni nanoparticles are amorphous in structure. The different ratio of Co: Ni influences the Co and Ni content that is proved by the EDS analysis. The phases formed during the synthesis are also changed depending on the Co: Ni ratio. Co-Ni nanoparticles synthesized at Co: Ni=1:1 and 4:1 ratio have a soft ferromagnetic behavior. On the basis of the Saturation magnetization, Ms [emu/g], the Co-Ni nanoparticles obtained at a ratio Co:Ni=1:1 and 4:1 have better magnetic characteristics than that in the case of a ratio Co:Ni=1:4 and also when graphite is used as asupport in the presence of β-cyclodextrin. These Co-Ni nanoparticle powders (Co:Ni=1:1 and 4:1) reveal a good ferromagnetic behavior, which would be suitable for biomedical applications as diagnostic tools and smart treatment agents in cancer and other diseases.