Numerical simulations of corrosion processes. Properties of the corrosion front and formation of islands

Abstract

Using a one-parameter model and a cellular automaton description we investigate the formation of a cavity in a material for which a small area has been deprotected and put in contact with an aggressive environment. Corrosion processes take place in a medium where the diffusion is assumed to be very rapid. We investigate the mean size of the cavity, the roughness of the corrosion front, the chemical composition of the front and the formation of islands resulting from the detachment of pieces of material. For the simulation times that we have investigated, a stationary regime is observed in which the relative composition of the front and the roughness become constant. An increase of the roughness produces the islands which leads to a smoothing of the front, and thus the roughness exhibits a maximum value. A mean field approach quite satisfactoryly reproduces the combination of processes involved in the corrosion model. Although we consider a one-parameter model, some results such as the value of roughness and its maximum are difficult to predict in a quantitative way.

Cellular automata approach to corrosion and passivity phenomena

“…Their application to corrosion problems also has a fairly long history [23,24]. In this paper, we reconsider our own contribution [25][26][27][28][29] to show the methods and lines of thinking that led us to an attempt at using cellular automata to model corrosion on passivating metal surfaces. Besides the mere elimination, neither micro-nor macroscopic descriptions are suited for our purposes, the argument to support our choice is that the phenomena we want to understand are rather general.…”

Mesoscopic modeling of corrosion processes: pitting morphology evolution

“…The model has been already presented elsewhere [12]. We recall here the points which are important for understanding of the new results presented in this work.…”

“…Hereafter we introduce anodic and cathodic reactions that can be separated in space. As a result of this separation heterogeneities in the distribution of H + and OH -ions can be formed [12]. Diffusion of these ions and their possible neutralization counteract the formation of these heterogeneities which determines the pit morphology.…”

“…Diffusion of these ions and their possible neutralization counteract the formation of these heterogeneities which determines the pit morphology. Since the pitting corrosion is a stochastic process in our model we use a stochastic cellular automaton (CA) as done in [12][13][14][15][16][17].…”

Cellular automata approach for morphological evolution of localised corrosion

“…metal/electrolyte interfaces. [7][8][9][10][11][12][13][14] They have the advantage of remaining simple and still be versatile. We introduce essentially two parameters l and e which define two regions and their respective corrosion rates.…”