Corrosion of Finely Dispersed Systems Based on Iron and Iron–Silicon Alloys in Neutral Media. I. Iron-Based Systems Prepared by Milling in Heptane and Heptane with Oleic Acid

Abstract

The corrosion resistance of finely dispersed metals in neutral media was studied by a method involving measurements of the volume of oxygen absorbed by a corroding sample. Iron powders were prepared by milling in heptane alone and heptane with oleic acid and tested for corrosion resistance in 0.85% NaCl at 37°C. An induction period characterized by a relatively low corrosion rate was revealed. The induction period is associated with a protective layer covering the powder surface; the layer contains oxides, graphite-like structures, and organic compounds. It was found that the protective properties of the surface layer are mainly determined by the oxide component; the mechanism of its formation depends on the milling medium and time.