Cr doping and heat treatment effect on core–shell Ni nanocluster film

Core–shell nickel (CS-Ni) and 5 at.% chromium-doped nickel (CS-Ni5Cr) nanocluster (NC) films, prepared by a nanocluster deposition system, were studied for heat treatment (HT)-induced structural, physical, and magnetic property alterations. Understanding the HT influence and oxidation mechanism at nanoscale can make these nanomaterials potential candidates for applications that involve stainless steel alloys. The contribution of Cr doping in altering the microstructural and relative oxidation kinetics was investigated in detail before and after the HT. The oxidation mechanism describes that the cation diffusivity increases following the doping of 5 at.% of Cr in Ni, which makes the oxidation rate of Ni5Cr HT higher than that of Ni-HT. At a temperature of 600 °C, a dramatic change was observed in surface morphology with many island-like nanostructures on the surface of Ni5Cr. The interface structure of the Cr-rich oxide layer plays a key role in the islands formation via agglomeration of NCs. The as-prepared and HT samples were analyzed by transmission electron microscopy, atomic force microscopy, magnetic force microscopy, energy-dispersive spectroscopy, and vibrating sample magnetometer to provide an insight on the effectiveness of chromium-doped nickel film.