Comparison of Aggressiveness Behavior of Chloride and Iodide Solutions on 304 and 304L Stainless Steel Alloys

Abstract

The aggressive effect of chloride anion in comparison to iodide anion on the pitting corrosion attack of 304 and 304L stainless steel (SS) alloys was investigated by using the cyclic potentiodynamic polarization test at 0.6 M Sodium Halide salts (NaX) solution and different temperatures. The two alloys 304 and 304L SS suffered from severe pitting corrosion at room temperature up to 50˚C in a chloride containing solution with the higher resistance observed for 304L in comparison to the 304 while on pits were detected in iodide solution for both alloys. The pitting potentials of the two alloys in 0.6 M NaCl solution reduced with the increase of the temperature. Examination of the alloys' surfaces was conducted by using the scanning electron microscopes where it revealed that the occurrence of pitting attack seems like hemispherical or irregular pits with different sizes.