Corrosion Studies of Austenitic and Ferritic Stainless Steels in Solution Containing Chloride Ions

Abstract

This paper investigated the corrosion behavior of AISI 304 and AISI 430 stainless steels in 3.0 wt. % NaCl solutions in both the presence and absence of pyridine or benzimidazole as inhibitor. The electrochemical study was performed using the polarization technique. Electrode surface morphology was characterized by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). The inhibition efficiency was evaluated at six different inhibitor concentrations (5, 25, 50, 100, 500, and 1000 ppm). The corrosion potential increased at all concentrations. For both alloys AFM showed that the average pit depth obtained in the presence of inhibitor was at least four times smaller than the values obtained in the absence of inhibitor.