Electrochemical Behavior of Fe3Al Modified with Ni in Hank's Solution

An investigation about the corrosion resistance of Fe3Al-type intermetallic alloys in Hank's solution was carried out via electrochemical techniques. The Fe3Al intermetallic alloy was modified with additions of Ni and evaluated in the as cast and thermal treated conditions. For comparison, Titanium and 316-L stainless steel were also evaluated. For evaluation purposes, electrochemical techniques included potentiodynamic polarization curves, open circuit potential measurements, linear polarization resistance curves and cyclic polarization curves were employed. Results shown that the 316-L stainless steel and titanium are the materials with greater corrosion resistance in chloride-rich environments showing an active-passive behavior and are susceptible to pitting corrosion. Compared to 316-L SS and Titanium, intermetallic Fe3Al alloys had greater susceptibility to pitting corrosion. Ni addition changed the corrosion potential of the intermetallic base Fe3Al to more noble values. Ni addition and thermal treatment improved the corrosion resistance of Fe3Al-base alloy owing to an increased stability of the passive layer.