The large-scale synthesis and characterization of Ni-core/Ag-shell (Ni@Ag) nanoparticles by the successive hydrazine reduction of nickel chloride and silver nitrate in ethylene glycol using polyethyleneimine (PEI) as a protective agent are described. The resultant Ni@Ag nanoparticles had a mean core diameter of 6.2nm and a shell thickness of 0.85nm, without significant change in the nickel concentration of 0.25-25mM for the Ag coating. Also, both Ni cores and Ag nanoshells had an fcc structure and PEI was capped on the particle surface. X-ray photoelectron spectroscopy analysis confirmed that the Ni cores were fully covered by Ag nanoshells. In addition, the Ni@Ag nanoparticles exhibited a characteristic absorption band at 430nm and were nearly superparamagnetic. Based on the weight of Ni cores, the saturation magnetization (Ms), remanent magnetization (Mr) and coercivity (Hc) were obtained as 17.2emug-1, 4.0emug-1 and 81Oe, respectively. Furthermore, the resultant Ni@Ag nanoparticles exhibited better anti-oxidation properties than Ni nanoparticles did due to the protection of the Ag nanoshells.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering
- Electrical and Electronic Engineering