Numerical simulation of the effect of grain size on corrosion processes: Surface roughness oscillation and cluster detachment

This work reports on the numerical simulation results of the grain size effect on the corrosion processes using a cellular automata model. The material considered consists of domains and their edges. The domains represent the monocrystalline cores while their edges represent the intergranular defects. Either a periodic pattern or randomly generated domains of Voronoï tessellation are used. The model parameters, taking into account the polycrystalline aspect of corrosion, are the domain density and the corrosion probabilities of metal grain core and grain boundary sites. The corrosion probability for grain edge is taken as higher than for the grain core. A complicated surface structure appears with a high geometrical roughness if the density of defects is not too high. A strong correlation between the roughness evolution, the metal crystalline properties and the corrosion mechanism of the metal dissolution was established.