The effects of KSCN addition and its concentration on the reactivation behavior of sensitized Alloy 600 in an H2SO4 solution were investigated. Single-loop electrochemical potentio-kinetic reactivation (SL-EPR), potentiostatic and potential decay tests were conducted in H2SO4 + KSCN solutions, including intermittent adjustment of the electrolyte composition and concentration. The SL-EPR results showed that the maximum current densities of the reactivation peaks increased with an increase in KSCN concentration from 0 to 0.05 M in the 0.5 M H2SO4 solutions. A decrease in the peak current density was observed, however, if the KSCN concentration was increased to 0.5 M. The potentiostatic test results at +400 m VSCE showed that sensitized Alloy 600 could be passivated in plain H2SO4 and KSCN solutions as well as in mixed H2SO4 + KSCN solutions. Potentiostatic tests at +30 m VSCE revealed that the presence of low KSCN concentrations made the passive film less stable in H2SO4 solutions, but it enhanced passivation at 0.5 M. The adsorption and desorption of SCN- and its subsequent redox reaction at different concentrations was discussed in relation to the reactivation of passive film formed on sensitized Alloy 600.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Science(all)