Electrochemical behaviour of Mo‐containing austenitic stainless steels in buffer solution

The effect of pH on the electrochemical behavior of austenitic stainless steels in naturally aerated and nitrogen‐deaerated buffer solutions has been studied. Potentiodynamic and ac impedance techniques were used. The results indicate that corrosion current (I corr ) decreases with pH. By examining the impedance data for the seven tested steels under various conditions, it seems that the total resistance (R T ) value is a suitable indication parameter for explaining the role of molybdenum and the other supplementary alloying additions (Ni, N, Cu and Mn) on the passive film behaviors as a function of pH of the forming solutions. As a general trend, the R T values for all steels tended to be lower in the basic buffer than in the acidic solutions.