Corrosion behavior of pure Al under Fe rust deposition: Decrease in the corrosion resistance of Al caused by γ-FeOOH

This study investigates the effect of γ-FeOOH on the corrosion behavior of pure Al. Polarization measurements in 0.5 wt% NaCl revealed that when the Al surface was entirely covered with γ-FeOOH, the corrosion resistance decreased. Grow discharge optical emission spectrometry and scanning transmission electron microscopy observations showed that Fe was incorporated into the surface film of Al, rendering the film inhomogeneous and decreasing in its protective ability. In addition, because γ-FeOOH readily causes the reduction reaction (cathodic reaction), the anodic reaction of Al was accelerated to balance with this increased cathodic reaction.