Characterization of corrosion products of Zn and Zn-Mg-Al coated steel in a marine atmosphere

摘要

The corrosion behaviour of pure zinc and zinc-magnesium-aluminium alloy (ZMA) has been studied dur-ing 6 months of exposure in marine environment (Brest, France). The composition of corrosion products is analysed using infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectros-copy (XPS). An improved corrosion resistance of ZMA is observed. This improvement is found to be connected to Mg~(2+) and Al~(3+) induced quenching of corrosion activity and to the enhancement of NaZn_4 Cl(OH)_6SO_4·6H_2O in the formed corrosion product.