Corrosion Behavior of Pre-treated Fe-Al Alloys in Aqueous Acid Solutions

摘要

The corrosion behavior of pre-treated Fe-Al alloy in a sulfuric acid solution and chloride-containing solution was studied. Alumina layer formed at 1073-1173 K on the surface of Fe-AI alloy improves the corrosion resistance of the alloy, whereas that at 1273 K does not improve it. This was explained by the defects of Al_2O_3 layer, the fraction of Al_2O_3 in the oxides, crystallity of Al_2O_3, and residual stress in the oxide layer. On the other hand, TiO_2 layer produced by dip coating and subsequent annealing at 523-773 K slightly improved the corrosion resistance of the alloy. The effect of the oxide layer on the aqueous corrosion was discussed focusing on the quality of the oxide.