Electrochemical corrosion behaviour of (100), (110) and (111) Fe3Al single crystals in sulphuric acid

In the present work the electrochemical corrosion behaviour of iron aluminide single crystals from a binary Fe3Al alloy in 0.5 M H2SO4 containing naturally dissolved O2 was investigated. The single crystal samples used in the experiments had surface orientations parallel to the low-index planes (100), (110) and (111) and were analysed by potentiodynamic polarization as well as electrochemical impedance spectroscopy. The results obtained showed that corrosion rates followed the trend (100) < (110) ≈ (111). Examination of the corroded surfaces revealed the presence of distinct patterns on each single crystal which indicated that the dissolution process was influenced by surface crystallography.