Effect of electrolyte composition on the electrochemical potentiokinetic reactivation behavior of Alloy 600

The effects of electrolyte composition and concentration on the reactivation behavior of Alloy 600 in H2SO4+KSCN solution were investigated by conducting single-loop electrochemical potentiokinetic reactivation (SL-EPR) tests. The experimental results revealed that two anodic peaks existed, which corresponded to pitting corrosion and matrix corrosion, respectively, in the reactivation polarization curve of non-sensitized Alloy 600. Alternately, for sensitized Alloy 600, an additional peak associated with grain boundary corrosion appeared in the potential range of +60 to −10 mVSCE within the reactivation polarization curve. The shape and current density of the reactivation curve of Alloy 600 with different degrees of sensitization varied with the electrolyte composition adjustments. A maximum peak anodic current density associated with grain boundary corrosion occurred when the concentration ratio of H2SO4/KSCN was 10 for the sensitized low carbon Alloy 600.