Influence of nitrogen ion implantation on the nanostructure and corrosivity of Ni/stainless steel substrates

Ion implantation is a surface modification technology to produce new material on the surface by impingement of high energy ions from the ion accelerator. In this work, AISI 304 stainless steels were coated with 90 nm Ni film by electron beam deposition and implanted by a flow of 5×1017 N cm−2 at 400 K temperature with different implantation energies of 10, 20, 30 and 40 keV. The prepared samples were corrosion tested in 3.5 NaCl solution using potentiodynamic polarization technique. Crystallographic and morphological structure of the samples were analyzed by Xray diffraction XRD and scanning electron microscope SEM respectively. A clear correlation between the physical analyses XRD and SEM and the potentiodynamic results is achieved. The highest corrosion resistance with a corrosion current density of 0.172 µA cm2 was achieved in case of sample which was N ion implanted at 20 keV energy.