Advanced Electrochemical modelling of atmospheric corrosion under thin film electrochemistry

摘要

The objective of this research is to contribute to the development of mechanistic electrochemical models for atmospheric corrosion and thin-film electrolytes. The typical top-down study of atmospheric corrosion is very cost- and time-consuming due to the high number of empirical tests, like outdoor exposure and experiments in accelerated conditions. On the other hand, mechanistic understanding of the corrosion system is obtained from laboratory experiments that focus on the (electro-)chemical nature of the underlying physical processes. However, both approaches are not able to accurately predict corrosion since the experimental conditions differ from the real atmospheric environment. The Multi-Ion Transport and Reaction Model (MITReM) is the link between the underlying electrochemical physics and corrosion rate. A bottom-up modelling approach is developed to link the quantified mechanics with the outcome of the corrosion system A major discrepancy with traditional electrochemistry is the confined nature of the electrolyte in atmospheric corrosion conditions and thin-film electrochemistry in general. The limited thickness has a direct effect on the diffusion layer thickness and local current density distributions. The effect of the oxygen solubility, diffusivity and electrolyte conductivity on the corrosion rate is studied with time-accurate simulations in evaporating conditions. The detection and analysis of corrosion products is essential in understanding the underlying mechanisms. The implementation of the formation of corrosion products is thus a vital aspect of the bottom-up model.This work contributes to the development of mechanistic models with a focus on the balance between electrochemical detail and industrial applicability. The broader scope is the development of a multi-scale framework towards the prediction of atmospheric corrosion and the development of methods for thin-film electrochemistry.