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 4 in simulated concrete pore solution (pH 12.8) on the corrosion behaviour of hot-dip galvanized steel (HDG). In the range of used MnO 4 - (10 -4 , 10 -3 , 10 -2 mol·L -1 ), 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 p /E corr and EIS. The composition of corrosion products is evaluated using SEM, XRD, XPS and AAS. The effective MnO 4 - ion concentration to prevent the corrosion of coating with hydrogen evolution is 10 -3 mol·L -1 ; lower concentrations only prolong the time to passivation (corrosion with hydrogen evolution). The highest used MnO 4 - concentration ensures corrosion behaviour without hydrogen evolution but also leads to the formation of less-protective amorphous corrosion products rich in Mn II /Mn III phases.