Corrosion Behavior of Hot-dip Zn-Al-Mg Coating Exposed to a Simulated Hot and Humid Marine Atmosphere
The work aims to explore the corrosion behavior and mechanism of hot-dip Zn-Al-Mg coatings in a hot and humid marine atmosphere and provide data references for hot-dip Zn-Al-Mg coatings serving in the hot and humid marine atmosphere.The corrosion behavior of the hot-dip Zn-Al-Mg coating in a simulated hot and humid marine atmosphere was analyzed by corrosion weight loss,X-ray diffraction(XRD),scanning electron microscopy(SEM),electrochemical impedance spectroscopy(EIS)and other test methods.The results showed that the corrosion product was mainly composed of Zn5(OH)8Cl2·H2O.After a period of corrosion,a small amount of ZnO and Zn5(OH)6CO3 were found.The corrosion product evolution was related to the participation of Mg in the corrosion process.The corrosion product had a lamellar structure,which was like a"sandwich"at 1 848 h.Compared with the upper and lower layers of dark substances,the bright-colored corrosion product in the middle layer had more Cl elements concentration.The corrosion rate of the hot-dip Zn-Al-Mg coating generally increased with time,and only dropped sharply in the stage of 672-840 h.Comparison of galvanized coatings corrosion in a simulated hot and humid marine environment and zinc corrosion in a hot and humid outdoor marine atmospheric environment showed that the hot-dip Zn-Al-Mg coating had high corrosion resistance in the simulated hot and humid marine atmosphere environment.The evolution of corrosion products of the hot dip Zn-Al-Mg coating in a simulated hot and humid Marine atmosphere is related to Mg in the corrosion process.The reason for the decrease of corrosion rate at 672-840 h is related to the decrease of ZnO and the increase of Zn5(OH)8Cl2·H2O in corrosion products.It is predicted that the hot-dip Zn-Al-Mg coating still has high corrosion resistance in the hot and humid harsh marine atmosphere,and it can be given priority as a construction material for hot and humid marine atmosphere environment.
国家科技期刊平台
NSTL
万方数据
维普
