Corrosion Behavior of N80 Steel under Immersion and Wet-dry Cyclic Condition

The polarization behavior of N80 steel was obtained from the corroded steel samples under wet-dry cyclic condition and compared with that from bare steel and immersion samples. The corrosion morphology and corrosion products of the steel samples were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The cathodic reduction of samples under wet-dry cyclic condition was controlled mainly by the charge transfer step of reduction of corrosion products rather than the limiting diffusion control of dissolved oxygen. The matrix metal of the samples was corroded and the rust itself also took part in the reduction processes and hence increased the corrosion rate of the steel samples under wet-dry cyclic condition.