Corrosion behavior of some austenitic stainless steels in chloride environments

The corrosion behavior of some Egyptian austenitic stainless steels SS 304L (I), SS 304H (II), SS 316H (III) and SS 304H (IV) was examined in 2.5 M NaCl solution. The study was performed using potentiodynamic polarization technique and complemented with XRD and SEM measurements. The electrochemical parameters Ecorr, jcorr and Epit were used to compare the corrosion resistances of the tested samples. The corrosion resistances of these samples in NaCl decrease in the order: alloy IV > alloy III > alloy II > alloy I. An increase in either NaCl concentration or solution temperature shifts Epit of all samples towards more negative (active) direction, indicating a decrease in their corrosion resistance. The increase in Mo or Cr content in the alloys of the stainless steels improves their corrosion resistance. The apparent activation energies, Ea0, of the general corrosion of the samples in 2.5 M NaCl solution were calculated.