The AC Corrosion Mechanisms and Models: A Review

Abstract

In this paper, the mechanisms and models of alternating current (AC) corrosion are critically reviewed to provide a systematic understanding for the further development of AC corrosion theory. None of the proposed mechanisms could give a full explanation of the AC corrosion behaviors, and no technical consensus has been reached. The models were gradually modified by relaxing the assumptions to more and more realistic situations, but no new concept was introduced in the improvement. Moreover, most of the proposed models were not verified by experiments quantitatively. Therefore, AC corrosion phenomena are far from comprehensive understanding and still need further study.

Galvanic Effect and Alternating Current Corrosion of Steel in Acidic Red Soil

“…In order to understand the acceleration effect and contribution of alternating current to corrosion, a mathematical model based on the Tafel equation was built to calculate the effect of AC [47,48]. Assuming that the corrosion process follows the Tafel equation, anode exchange current intensity I0, a remains constant with AC interference when the sample is subjected to AC with the amplitude of V and angular frequency of ω:…”

On the Dynamic Stability of Gold Electrodes Exposed to Alternative Voltages in Microfluidic Systems

“…x T HCl 2 0 Cl 0 Even though anodic gold dissolution under constant voltage (CV) has been characterized by a range of methods including cyclic voltametry with rotating electrodes, 18,19,22,23 in-situ quartz crystal microbalance, 17,18 in-situ scanning tunneling microscopy 20 and inductively-coupled plasma mass spectrometry 19 and is relatively well understood, the alternative voltage (AV) case is far more complex. 24,25 Several timescales must now be distinguished (i) the period of the electrical oscillations, (ii) a much slower timescale to analyze the electrode dissolution, (iii) the charging timescale of the electrical double layer, (iv) fundamental reaction kinetics timescales.…”

“…35 In the context of rectification, mass transfer effect on AV dissolution has been considered by Bosch and Bogaerts 36 but at only a single frequency. In a recent review on the topic, Zhang et al 24 points to several limitations: (i) only one theoretical model of electrode dissolution in AV has been compared to experiments (steel electrode in soil), but a single electrolyte composition and frequency were considered, 37 (ii) the mathematical complexity of the models and large nonlinearity hinders simple analytical expressions and therefore do not provide an intuitive picture of the dissolution laws, (iii) the effects of mass transfer have been overlooked in the models. Another limitation, not mentioned by Zhang et al, 24 is the effect of scale on the dissolution voltage.…”

“…In a recent review on the topic, Zhang et al 24 points to several limitations: (i) only one theoretical model of electrode dissolution in AV has been compared to experiments (steel electrode in soil), but a single electrolyte composition and frequency were considered, 37 (ii) the mathematical complexity of the models and large nonlinearity hinders simple analytical expressions and therefore do not provide an intuitive picture of the dissolution laws, (iii) the effects of mass transfer have been overlooked in the models. Another limitation, not mentioned by Zhang et al, 24 is the effect of scale on the dissolution voltage. For instance, experiments using inter-electrode gaps of only a few micrometers 38 have shown that megahertz range frequencies were needed to achieve electrode protection akin to those in the kHz range described in the present work where we used millimetric electrode gap.…”