Effect of nitrogen on the corrosion behavior of austenitic stainless steel in chloride solutions

The effect of partial replacement of nickel with nitrogen on the mechanism of localized corrosion resistance and repassivation for nitrogen-bearing stainless steel was investigated using anodic potentiodynamic polarization technique. The solutions used for this study contained 0.0, 0.05 and 0.33 M Fe3+ for solutions I, II and III, respectively, in a total Cl− ion concentration 1 M. The pitting attack was found to be retarded by nitrogen addition and the samples were able to passivate as the nitrogen increase. Addition of nitrogen allows the decrease in the wt.% of Ni, but to a certain limit. Nitrogen is adsorbed on the interface of the metal oxide and results in the repulsion of Cl− ions. Moreover, it reacts with H+ ions in the solution leading to higher pH, which explains the retardation effect of nitrogen to corrosion.