Influence of nitrogen implantation on the localized corrosion resistance of different tempers of AA7075 aluminium alloy

Abstract

This paper reports the study of the effect of nitrogen implantation on the localized corrosion resistance of the passive layers generated on different tempers of AA7075 aluminium alloy.Cyclic potentiodynamic polarization has been employed to analyze the resistance to localized corrosion of the alloys in a chloride medium, whereas exfoliation corrosion susceptibility test (EXCO-Test) have been performed to evaluate the influence of nitrogen implantation on exfoliation resistance.Results show that nitrogen implantation (dose of 2 × 10 17 N + ions/cm 2 and energy of 50 keV) does not have a clear positive effect on exfoliation resistance as it is evident on EXCO testing. However, electrochemical experiments performed in 1 mM NaCl solution reveal a light increase on localized corrosion resistance on implanted alloys. Moreover, the results demonstrate that the susceptibility of the 7075 aluminium alloy to different types to localized corrosion such as, pitting, intergranular and exfoliation greatly depends on the aging treatment, even under implantation conditions.