Corrosion Products of Iron Dissolution—Dependence on Anions in Solution

This paper deals with the identification of certain species produced during the corrosion of iron in oxygen-containing and oxygen-free solutions. Iron was allowed to corrode in acid solutions of constant pH of NaBr, NaCl, Nal, NaNO₃, Na₂HPO₄, Na₂SO₄, and NaClO₄. These reactions were conducted in (1) air-saturated solutions, (2) solutions purged with N₂, and (3) a closed argon-purged system. The reactions were carried out in a special optical cell in an Hitachi EPS-3T spectrophotometer and measurements were made over the ultra-violet and visible regions. The results obtained in the air-saturated solutions indicated that although many of the spectra exhibited common features the spectra were unique for each individual solution. Thus the species arising in the dissolution process were dependent on the anion in solution.