Aluminum anodizing ‘chamfering’ growth model using pattern recognition and electric field simulation

The anodizing process deeply affects the properties of anodized aluminum foils, but current research on anodizing focuses mainly on the process itself, with a paucity of systematic studies on the mechanisms of oxide film formation. In this study, it is found that there is a tendency for the alumina pits from square to circular during the anodizing process. Based on the electric field simulation of Comsol Multiphysics (COMSOL) software, a model of ‘chamfering’ growth of the oxide film is proposed, and the model is verified by energy dispersive spectroscopy (EDS) test and image pattern recognition. In addition to the visualization model, we can also get the following patterns: ‘chamfering’ phenomenon at the oxide film deepens with the increase of the formation voltage; the alumina grows less to the inside at low voltage, and grows gradually after the voltage increases. In this study, ‘Alumina Pit Evolution Diagram’, similar to the phase diagram in thermodynamics, is also developed to define the types of alumina pits in different anodizing environments. Based on the obtained laws and diagrams, we can greatly fill the theoretical gap in the oxide film growth section, which in turn will guide the improvement of the actual production process.