Corrosion resistance of austenitic stainless steels in non-aqueous neutral chloride solution

Abstract

The corrosion resistance of two standard austenitic stainless steels (AISI 304 and 321 SS) has been investigated in non-aqueous methanolic solution containing lithium chloride. The effect of chloride concentration on the general corrosion behaviour of the steels has been investigated using open circuit potential (OCP), potentiostatic polarization and scanning electron microscopic (SEM) techniques. Both the steels have undergone active corrosion. The rate of corrosion is found to depend directly on the concentration of chloride ion in methanol similar to the aqueous solutions. The polarization measurements reveal that the corrosion resistance of the Ti-alloyed 321 SS is superior as compared to the 304 SS due to the presence of titanium in it. AISI 321 SS suffer from pitting corrosion whereas grain boundary attack is apparent in 304 SS.