Inhibitive effect of sodium molybdate on the corrosion behavior of galvanized steel in simulated concrete pore solution

Abstract To limit rapid dissolution of zinc and hydrogen evolution of zinc coating in fresh concrete environments at the early stage, the corrosion inhibition of sodium molybdate for galvanized steel in simulated concrete pore solutions with/without chloride ion addition was studied. The inhibitive effect of sodium molybdate was assessed by open circuit potential (OCP), potentiodynamic polarization test, polarization resistance measurement, scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) and X-ray photoelectron spectroscopy (XPS) tests. The results showed that the formation of a Mo-containing film at the corroding interface occurred, which acted as a barrier effect to suppress the rapid dissolution and hydrogen evolution of the zinc layer in the high alkaline environments. Meanwhile, the presence of sodium molybdate also modified the formation and properties of the corrosion products formed on the sample surface.