Self-Organization Kinetics of Microarc Oxidation: Nonequilibrium-State Electrode Reaction Kinetics

Abstract

Here, we present a new method for studying and gaining new insights into microarc oxidation (MAO) and its corresponding nonequilibrium-state electrode reaction kinetics. We observed that the fundamental condition of microdischarge formation was the resistance nonequilibrium in the oxide film caused by the existence of a defective region. Specifically, the current always first passed through a path with the lowest resistance. After the first discharge, a ceramic phase (e.g., alpha-Al2O3) was formed, which changed the conductive properties of the defective region, and the resistance in the defective region was subsequently increased, which sent feedback to the next current distribution. This fundamental and inherent law rendered controlling and predicting the microarc system kinetics by the external environment difficult. Therefore, we developed a microarc algorithm and proposed a feedback coefficient k, which determines whether the anode current distribution is inclined to or deviates from the equilibrium state. Finally, we analyzed the k-frequency relationship and used frequency to experimentally describe various kinetic behaviors of MAO. (C) The Author(s) 2016. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved.