Passivity of Nickel-Containing Stainless Steels in Concentrated Sulphuric Acid

The spontaneous periodical oscillation of corrosion potential between the active and passive states, typical of nickel-containing stainless steels in concentrated (93.5%) sulphuric acid is used to determine the nature of passivity in such systems. Detailed analysis of the electrochemical kinetics of the oscillating potential in combination with (ex-situ) surface analysis has indicated the presence of nickel sulphides with a limited potential …