The Influence of Graded Amount of Potassium Permanganate on Corrosion of Hot-Dip Galvanized Steel in Simulated Concrete Pore Solutions.

This paper evaluates the amount of KMnO in simulated concrete pore solution (pH 12.8) on the corrosion behaviour of hot-dip galvanized steel (HDG). In the range of used MnO (10, 10, 10 mol·L), corrosion behaviour is examined with regard to hydrogen evolution and composition (protective barrier properties) of forming corrosion products. The corrosion behaviour of HDG samples is evaluated using R/E and EIS. The composition of corrosion products is evaluated using SEM, XRD, XPS and AAS. The effective MnO ion concentration to prevent the corrosion of coating with hydrogen evolution is 10 mol·L; lower concentrations only prolong the time to passivation (corrosion with hydrogen evolution). The highest used MnO concentration ensures corrosion behaviour without hydrogen evolution but also leads to the formation of less-protective amorphous corrosion products rich in Mn/Mn phases.