Preparation And Capability Research Of Magnetic Nanocapsules

BN-coated Co Nanocapsules,Co-Al composite oxide-coated Co nanocapsules and Ag-coated Ni nano-composite powders were prepared by arc discharge and electroless deposition,respectively,using Co-B amorphous,Co-Al alloy,Ni taken as target.The phase structure,shape appearance,surface component and magnetism of the nanocapsules are characterized by X-ray diffraction,energy diffraction spectrum,high resolution electricity transmission,scanning electricity transmission,infrared spectrum,photoluminescence, vibrate sample magnetism and other means.It include three parts.First,Co-B amorphous alloy powders were prepared by solid chemistry reaction,then Co/BN nanocapsules were prepared by arc charge method using Co-B alloy target as anode in N₂ and the Ar atmosphere.Secondly,Co-AI composite oxide-coated Co,Co-Al solid solution nanocapsules were prepared by arc discharge in He atmosphere,using W as cathode and Co-AI alloy as anode.Thirdly,Ag-coated Ni nano-composite powders were synthesized by electroless deposition Ag using Ni nanoparticles as matrix material.The research result shows that Co/BN nanocapsules successfully prepared by arc discharge,which of the size is 30～100 nm.HRTEM revealed the particles have distinct shell/core structure.That the shell is BN was identified by infrared spectrum and photoluminescence.Magnetism research indicates that the saturation magnetization of nanocapsules decresses and the coercive force of nanocapsules increases,compared with pure Co crystallite powders.Nanocapsules of Co-Al composite oxide coating Co,Co-Al solid solution were also synthesized by arc discharge.It is approved that the core is comprised of body-centered cubic and hexagonal structure of the cobalt nanoparticles and Co-Al solid solution,and the shell is Co-Al composite oxides measured by EDS,XRD and XPS spectrum.Nanocapsules of Ag coating Ni were successfully synthesized by electroless deposition.Ag and Ni phases were characterized by using X-ray diffraction (XRD) after electroless deposition Ag,at the same time HRTEM selected diffraction also proves there exist separate Ag particles in as-prepared composites powders.Due to the chemical activity of Ag is far lower than that of Ni,the existence of Ag outside layer greatly improves the stability of Ni nanoparticles and increases the capacity of antioxidation.The synthesis of Ag—coated Ni nanoparticles will reduce the cost of the conductive,compared to absolute Ag,thereby it has significant applying value.