Influence of Anions on the Structure and Morphology of Steel Rust Particles Prepared by Aerial Oxidation of Acidic Fe（II） Solutions

Abstract

In order to simulate the atmospheric corrosion of steel, artificial steel rust particles were synthesized by aerial oxidation of aqueous solutions containing FeC_l2, FeSO₄ and NaNO₃ and the structure and morphology of the obtained particles were characterized by XRD and TEM. Needle-like SO₄^2- containing Schwertmannite （Fe₈O₈（OH）₆（SO₄）） particles were formed in FeCl₂-FeSO₄, FeSO₄-NaNO₃, FeCl₂-FeSO₄-NaNO₃ solutions and the crystallization and particle growth of this material were not altered by added Cl^- and NO₃^-. While, the spindle-shaped β-FeOOH particles were formed from in only FeCl₃-NaNO₃ solution, though no marked change in crystallite and particle sizes of β-FeOOH was recognized by adding NO₃^-. Accordingly, it can be suggested that the corrosive SO_X gas strongly affects on the rust formation in atmospheric corrosion of the steels.