Revised Pourbaix diagrams for iron at 25-300 degrees C

The Pourbaix diagrams, potential pH diagrams, for iron at 25-300 degrees C have been revised. The selection of thermochemical data has taken into account the experimental solubility of magnetite at T = 10-300 degrees C. Temperature extrapolations of thermochemical data for aqueous species have been performed with the revised Helgeson-Kirkham-Flower model, which also allows uncharged aqueous complexes to be handled. The Pourbaix diagrams show a stability region for ferrous hydroxide, Fe(OH)(2)(cr), at 10(-6) m and T less than or equal to 85 degrees C, implying that the Schikorr reaction is not thermodynamically possible above this temperature. A corrosion region between iron and magnetite exists at all temperatures in high purity water (10(-8) m), due to the hydrolysis products of iron(II). Copyright (C) 1996 Elsevier Science Ltd