Corrosion behaviors of austenitic Fe–30Mn–7Al–xCr–1C alloys in 3.5% NaCl solution

The corrosion behaviors of the as-quenched Fe–30 wt.%Mn–7 wt.%Al–x wt.%Cr–1 wt.%C alloys (x = 0, 3, 6 and 9) in 3.5% NaCl have been investigated. Passivation could be observed for all the alloys except for the alloy without Cr content. The corrosion potential (Ecorr) and pitting potential (Epp) increased pronouncedly with increasing Cr content up to 6 wt.%, and decreased as Cr content up to 9 wt.%. The decrease of Ecorr and Epp of the alloy containing 9 wt.% Cr was due to the formation of (Fe,Mn,Cr)7C3 carbides in the austenite matrix and on the grain boundaries. It is noted that the corrosion behaviors of the austenitic Fe–Mn–Al–Cr–C alloys with higher Cr (≥3 wt.%) content have never been reported in previous literatures.