Prepassive range

The ability to interpret DC and AC data by a unique model in the active, transition, and prepassive range... 

Around 1980, some branching mechanisms were proposed with the intention of describing the processes occurring in the active, transition, and prepassive ranges of the overall active state, and explaining the different values of the experimental kinetic data obtained by their authors. In addition to this, the supporters of the consecutive electron-transfer concept offered an explanation for the disagreement between the experimental low steady-state Tafel slope and the inductive behavior of the electrode, on the one hand, and the theoretical predictions, on the other, as demonstrated by Plonski " since 1969. 

The self-catalytic path via Fe (II)ad formation was introduced to account for the increased number of inductive loops when the polarization encompassed the transition and the prepassive ranges. 

Both catalytic paths introduced in this model were previously proposed by Lorenz et al. [78-81] for interpreting the prepassive dissolution range. 

Active and Active-Passive Transition Impedance and Frequency-Resolved RRDE Measurements The assoeiation of impedanee and fiequency-resolved RRDE techniques initially introduced for iron [38,117,197] has been extensively applied to the prepassive and passivation ranges of Fe-Cr alloys with and without chloride added [174,194,195], Of course, the interpretation is more intricate than for pure metals (even with multiple dissolution valences). For kinetic reasons, Cr species are not detectable on the ring. In order to draw unambiguous conclusions, reasonable assumptions had to be made concerning simultaneous alloy dissolution at steady state (see thermodynamics and rate constant approach earlier) and dissolution valences of Cr. 

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