Formation of magnetite rust particles by reacting iron powder with artificial α-, β- and γ-FeOOH in aqueous media

To simulate the atmospheric corrosion of steels, magnetite (Fe3O4) rust particles were prepared in aqueous media containing iron powder (alpha-Fe) and artificial alpha-, beta- and gamma-FeOOH particles at pH = 6.0 and 50 degrees C for 24 h. The Fe3O4 formation was not recognized by treating the iron powder with alpha-FeOOH. When the iron powder treated with beta- and gamma-FeOOH, these materials were dissolved to generate Fe3O4 and alpha-FeOOH particles. The amount of formed Fe3O4 particles was in the order of beta-FeOOH > gamma-FeOOH >> alpha-FeOOH, which was strongly related to the density and solubility of FeOOH. (C) 2013 Elsevier Ltd. All rights reserved.