Effect of nitrogen on the electrochemical behavior of 301LN stainless steel in H2SO4 solutions

The effect of nitrogen on the electrochemical behavior of 301 stainless steel in sulfuric acid solutions was investigated. The results of electrochemical potentiokinetic reactivation tests show that the degree of sensitization of 301LN stainless steel is less than that of 301 stainless steel. The alloying of nitrogen into 301 stainless steel causes a decrease in the passive current density and an increase in the polarization resistance in 10% sulfuric acid solution. Electrochemical impedance spectroscopy data also indicate that the polarization resistance increases with increasing nitrogen content in the steel at open circuit potential and at +400 mV versus a sat-crated calomel electrode. Potential decay measurements show that the passive film formed on 301LN stainless steel is more stable than that on 301 stainless steel. The results of X-ray photoelectron spectroscopy reveal that NH, formed on the surface of the nitrogen containing 301 stainless steel after immersing in sulfuric acid at +400 mV for 2 h. (C) 1997 Elsevier Science S.A.