Simulation of pit interactions of multi-pit corrosion under an anticorrosive coating with a three-dimensional cellular automata model

Abstract

To study the corrosion process and the pit interactions of multi-pit corrosion covered by an anticorrosive coating, we present a three-dimensional cellular automata model that is efficient of modeling multi-pit corrosion the spatial separation of anodic and cathodic semireactions results in the interaction of pits. Through the corrosion simulation of different number of pits, when there are more than one pits, some pits grow much faster than single-pit case, while some other pits filled with basic ions may stop growing for a long time. Therefore, the heterogeneous distribution of pH in multi-pit corrosion can be observed in the simulation results, and they are shown to be consistent with experimental studies. Specially, the concentration of basic ions in some areas can be seen both from the modal and the experimental results. The permeability of breakdown anticorrosive coating is considered in the model, and the results show that it plays an important role in the corrosion process.