CORROSION BEHAVIOR OF STAINLESS-STEEL (AISI 321) IN ALCOHOLIC-H2SO4 MIXTURES

The electrochemical and corrosion behaviour of austenitic stainless steel (AISI 321) in alcoholic environment containing different contents of H2SO4 has been investigated. The electrochemical polarization curves of the stainless steel in ethanol, iso-propanol and t-butanol containing 0.001-1 kmol/m3 H2SO4 show active, passive and transpassive behaviour. The critical current density for passivation, current density in the passive state and the potential range of passivity has been found to depend on the concentration of acid and the type of alcohol in alcohol-H2SO4 mixtures. The stainless steel suffered localized attack due to pitting in ethanol containing higher concentrations of H2SO4. The results have been discussed in light of physicochemical properties of the alcohols.