Corrosion behaviour of 304 stainless steel in dioxane

Corrosion kinetic of 304 stainless steel in dioxane solution has been studied using potentiostatic technique, 304 stainless steel exhibits a long stable passivation range in pure dioxane. Addition of water, however destabilizes the film and at a concentration of >1%, the metal comes in an active state. The electrode potential of the metal shifts in active direction with the addition of water in the solvent, which is more, pronounced just after the immersion of metal. Contamination of the solvent with different acids has a strong activation effect on the corrosion process. Amongst the acids studied, hydrochloric acid has the strongest deleterious action followed by perchloric, sulphuric and phosphoric acids. Active-passive type of polarization curve for the metal has been noted in dioxane-sulphuric acid systems. Presence of chloride ion in the solvent has a strong depassivation tendency, which causes the pitting type of attack in the presence of H+ ions. Potential time plots that the additives depolarize the anodic reaction resulting in a strong deleterious towards corrosion process.