Contribution to the Interpretation of Current Maxima in the Passivity Range of Austenitic Stainless Steels Available to Purchase

Passive current density maxima have been observed by various workers during the anodic polarization of different stainless steels in sulfuric acid solutions and have been explained by many theories. This paper describes the precorrosion time and some other pretreatments of the sample surface which change drastically the anodic polarization curve of AISI Type 304 stainless steel in 2N H₂SO₄, lowering the critical current density and causing two passive maxima. Our results are used in a critical analysis of the conclusions of other authors. The passive current density maxima are attributed to the oxidation of hydrogen formed during precorrosion and absorbed into the alloy and of ions present in the solution and coming from the alloy dissolution.