Surface nanostructure modification of Al substrates by N+ ion implantation and their corrosion inhibition
(Department of Physics, University of Tehran, North-Kargar Street, P. O. Box 143951547, Tehran 1439955961, Iran)
Abstract: The influence of implantation of N+ ions of different energies on the nanostructure of 7049 Al substrates and the corrosion inhibition of produced Al samples in a 3.5% NaCl solution was studied. The X-ray diffraction (XRD) results confirmed the formation of AlN as a result of N+ ion implantation. The atomic force microscope (AFM) results showed that grains of larger scale are formed by increasing N+ energy which can be due to heat accumulation in the sample during implantation causing higher rate of diffusion in the sample, hence decreasing the number of defects. Corrosion resistance of the samples was studied by the electrochemical impedance spectroscopy (EIS) measurements. Results showed that corrosion resistance of implanted Al increases with increasing N+ ion energy. The equivalent circuits for the N+ implanted Al samples with different energies were obtained, using the EIS data which showed strong dependence of the equivalent circuit elements on the surface morphology of the samples. Finally, the relationship between corrosion inhibition and equivalent circuit elements was investigated.
Key words: ion implantation; aluminum; corrosion; electrochemical impedance spectroscopy; equivalent circuit