The effect of Ni and Si elements on the corrosion behavior of weathering steels (WS) exposed to the simulated coastal environment was investigated by electrochemical measurement methods such as electrochemical impedance spectroscopy (EIS) and polarization technique. Morphology of specimens was studied using scanning electron microscopy and energy dispersive spectrometry. In polarization tests, with increasing Ni and Si content in WS, corrosion potential values shifted to more positive values and also the corrosion current density showed the lower values representing the higher corrosion protection. Fitting the EIS data to an appropriate equivalent electrical circuit demonstrated that the highest protection belonged to a WS0.5Si-0.5Ni sample that was consistent with polarization results. In fact, the density of the formed rust layer along with a good barrier function prevented remarkably the higher corrosion of the surface. It means that the passages of charge transfer were blocked and the dissolution reaction of metal surface carried out difficulty.
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