Effect of chromium content on corrosion Behaviors of Fe-9Al-30Mn-(3,5,6.5,8)Cr-1C alloys

Abstract

The corrosion behaviors of the as-quenched austenitic Fe-9%Al-30%Mn-(3,5,6.5,8)%Cr-I %C (in mass%) alloys in 3.5 % NaCI solution have been examined. Passivation could be observed for all of the four alloys. The corrosion potential (E-corr) and pitting potential (E-pp) increased pronouncedly as Cr content increased from 3 to 5%, and decreased as Cr content up to 6.5 and 8%. The decrease of E-corr and Epp of alloys containing 6.5 and 8% Cr was due to the formation of (Fe,Mn,Cr)(7)C-3 carbides within the austenite matrix and on the grain boundaries. The present result indicates that the Fe-9%Al-30%Mn-5%Cr-l%C alloy exhibited the highest corrosion resistance in 3.5% NaCl solution. It is worthy to note that the corrosion behaviors of the austenitic FeAlMnCrC alloys with higher Cr (>= 3%) content have never been reported in previous literature.