Effects of Cl− and AC on the Corrosion Behavior of 2507 Super Duplex Stainless Steel in a Simulated Concrete Pore Solution

Abstract

The effects of Cl− concentration and applied alternating current (AC) on the corrosion behavior of 2507 super duplex stainless steel (SDSS) were studied in a saturated Ca(OH)2 solution by electrochemical measurements, immersion test, and x-ray photoelectron spectroscopy. The results show that the presence of Cl− ions accelerates the corrosion of 2507 SDSS in the saturated Ca(OH)2 solution. The protective ability of passive film decreases as Cl− concentration increases, especially at the concentration of 10% Cl−. As the applied iAC increases, the ip value increases, and the Ep value decreases. The applied AC increases the number of defects within the passive film, affects the electronic property of the surface film, which results in a harmful effect on the passive film, and weakens its anti-corrosion property. The higher the iAC, the more severe the damage influence is. Moreover, imposed AC promotes the pitting corrosion sensitivity of SDSS and enhances its corrosion rate. The applied AC and the addition of Cl− exert a combined effect, reducing the corrosion resistance of passive film formed on 2507 SDSS.