Influence of Fe(II) and Fe(III) on the formation, structure and molecular adsorption properties of zinc hydroxysulfate rusts

To simulate the corrosion of galvanized steel, artificial zinc rust of zinc hydroxysulfate (Zn4(SO4)(OH)6·nH2O:ZHS·nH2O) was prepared in the presence of Fe(II) and Fe(III) at 85 °C. Adding Fe(II) and Fe(III) suppressed the crystallization, particle growth and adsorption of corrosive gasses such as CO2 and SO2 on ZHS·nH2O. The effect of Fe(III) was much higher than that of Fe(II). On increasing Fe(III) added, the crystal structure turned following as ZHS·nH2O → a mixture of ZHS·nH2O and α-FeOOH → α-FeOOH and altered the particle morphology from hexagonal plate to needle-like nanoparticles.

► Artificial zinc hydroxysulfate (ZHS) rust was prepared with Fe(II) and Fe(III).
► Adding Fe(II) and Fe(III) suppressed the crystallization and particle growth of ZHS.
► The effect of Fe(III) on the formation of ZHS was much higher than that of Fe(II).
► Existence of Fe(III) would form compact and dense zinc rust layer on the steel.