Influence of inhibitors on the corrosion behavior of the X5CrNi18 10 stainless steel ‐ welded joint

Abstract

This study considers the corrosion behavior of the X5CrNi18 10 stainless steel‐welded joint in NaCl solution, with and without the presence of several corrosion inhibitors (NaNO3 , Ce(NO3)3, and CeCl3). The degree of sensitization of the welded joint to intergranular corrosion is determined using the electrochemical potentio kinetic reactivation method with a double‐loop method. Pitting corrosion tests are performed by the potentiodynamic method. Resistance to general corrosion and the stability of the passive film is assessed based on the results of electrochemical impedance spectroscopy measurements, as well as on the values of the corrosion and passivation current. The main goal of this study is to determine the relation of the welded joint microstructure to general and pitting corrosion in the presence of the corrosion inhibitors. The value of pitting potential for the base metal and weld metal in the presence of the NaNO3 or Ce(NO3)3 inhibitor is shifted to potentials in the transpassive area. The pitting potential for the heat‐affected zone also possesses a noticeable higher value. However, nitrate ions do not increase the general corrosion resistance of any part of the welded joint. CeCl3 does not increase resistance to general or pitting corrosion.