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

Abstract

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 ( E corr) and pitting potential ( E pp) increased pronouncedly with increasing Cr content up to 6 wt.%, and decreased as Cr content up to 9 wt.%. The decrease of E corr and E pp of the alloy containing 9 wt.% Cr was due to the formation of (Fe,Mn,Cr) 7C 3 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.