Influence of Conductivity on Corrosion Behavior of 304 Stainless Steel in High Temperature Aqueous Environment

The influence of conductivity on corrosion behavior of 304 stainless steel (SS) in high temperature water was investigated by using in-situ potentiodynamic polarization curves, electrochemical impedance spectra (EIS) at 300 °C, and ex-situ scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The structures of oxide films formed on 304 SS change with different conductivities at 300 °C. With the increase in conductivity, the passive current density increases while the resistances of oxide films decrease. But the resistances do not decrease lineally with the increase in conductivity. A modified double-layer model for oxide structure was proposed to explain the influence mechanism of conductivity on the oxide films on 304 SS in high temperature water. Improving the 10B enrichment level can reduce the conductivity of primary water and increase the corrosion resistance of 304 SS.