Open AccessCorrosion Resistance of Hot-dip Zn55Al Coated Steel Sheet Treated by Cr(III) Conversion Coating Against Chloride-Containing Media
Author(s) -
Jie Pan,
Yan Li
Publication year - 2019
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/562/1/012020
Subject(s) - corrosion , coating , dielectric spectroscopy , passivation , materials science , scanning electron microscope , chloride , metallurgy , electrochemistry , dip coating , composite material , electrode , chemistry , layer (electronics)
Under the influence of chloride-containing environment such like shallow sub-marine or littoral area, hot-dip Zn55Al coated steel sheet is easily corrode. Based on an applicable combination of parameters, a Cr(III)-based conversion coating(TCC) was formed on Zn55Al coating successfully based on Coldip 120 commercial passivator. The corrosion behaviour of the Cr(III) treated hot-dipped steel samples subjected to the Cr(III)-based passivation treatment was studied using electrochemical impedance spectroscopy (EIS) in a 3.5% NaCl solution, and the failure mechanism of the conversion coating-hot-dip coating system was investigated by analysing the time dependence of the electrochemical parameters of impedance. In addition, the role of corrosion products formed on Zn55Al during the different immersion time in the NaCl solution was also revealed by scanning electron morphology (SEM) and energy dispersive spectrometer (EDS).