Electrochemical Study on Depassivation of Galvanized High-Strength Steel Wires
LI Bei
ZHANG Juhui
HE Jiacheng
CHI Lin
GUAN Zhongguo
Abstract：Electrochemical methods were employed to analyze the depassivation mechanism of the passivation films on galvanized high-strength steel wires in simulated concrete solution with different chloride concentrations.The results indicate that,as the testing progresses,an increasingly severe hydrogen evolution reaction occurs at the cathode of galvanized high-strength steel wire with the corrosion rate reaching its peak in 5%-7%NaCl simulated concrete solution.With the increase in chloride concentration,the impedance spectrum radius of galvanized high-strength steel wires exhibits a trend of initial slow decrease followed by a sharp decline.After pitting corrosion occurs on the wire,the generated corrosion products cover the wire surface,inhibiting further ingress of chloride.The depassivation mechanism of the wire is characterized by the destruction of the passive film on the wire surface due to chloride erosion,with ZnCl2 diffusing to the surface of the passive film and combining with OH-in the solution to generate corrosion products such as ZnCl2·4Zn(OH)2·H2O.The critical chloride concentration causing wire corrosion is 4%.Beyond this threshold,the rupture of the passivation film on the wire is accelerated,hastening the onset of corrosion.Based on the impedance characteristics of galvanized high-strength steel wires in simulated concrete solutions with different chloride concentrations,the impedance spectrum data fitted by the dual time-constant equivalent circuit model(b)match well with the experimental data.
Keywords：galvanized high-strength steel wirechloride concentrationelectrochemical impedance spectroscopycorrosion resistancedepassivation mechanism
Publication Date：2024-11-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：9( 996-1003,1032 )