The Electrochemical Reduction of Rust Films on Weathering Steel Surfaces

The electrochemical reduction of α‐, γ‐, δ‐, and amorphous FeOOH was investigated. These oxides were applied as pastes to weathering steel substrates and galvanostatically reduced in solutions of 0.1 M Na 2 SO 4 . Raman and infrared spectroscopy were used to monitor the reaction products. Amorphous, γ ‐ , and δ ‐ FeOOH were reduced to magnetite, Fe 3 O 4 , under the experimental conditions of this investigation; however, α ‐ FeOOH was not reduced under these conditions. The atmospheric corrosion product formed on a weathering steel light standard was entirely reduced to Fe 3 O 4 and had a galvanostatic reduction curve similar to those for γ ‐ , and δ ‐ FeOOH .