Corrosion performance of carbon steel in N-doped mesoporous carbon spheres (NMCS)-containing alkaline medium in presence of chloride

Abstract

The electrochemical response of carbon steel in chloride-free or chloride-containing 0.1 M and 0.9 M NaOH, in the presence of 0.016 wt.% NMCS, is the subject of this work. The NMCS exhibited a negative (in 0.1 M NaOH) and positive (in 0.9 M NaOH) zeta-potential. This determined altered steel electrochemical response, improved overall, especially in chloride-containing 0.9 M NaOH. The effect was related to an enhanced Fe3+ contribution in the passive film, when NMCS were present. The improved corrosion resistance was also attributable to a NMCS-triggered competition of OH− vs. Cl− ions in the medium, in other words, NMCS interference to promote passive layer stability.