Electrochemical Corrosion Behavior of 000Cr25Ni20 Austenitic Stainless Steel in Nitric Acid Solution

The electrochemical corrosion behavior of 000Cr25Ni20 austenitic stainless steel in nitric acid solution at different temperatures and in different concentrations were investigated.The results showed that the free corrosion potential of 000Cr25Ni20 stainless steel was shifted towards to transpassive zone and the range of the passive zone reduced with the rise of both nitric acid concentration and temperature.At passive potential,a capacitive loop with great value of radius appeared in the electrochemical impedance spectroscopy (EIS).The influence of nitric acid concentration on the EIS was not obvious at the same passive potential.In passive/transpassive transition zone,with intergranular corrosion occurred,a inductive loop appeared at low frequency area.The radius of the capacitive loop at high frequency decreased sharply because of the impedance value of passive film severely decreasing.