Towards multiscale modelling of localised corrosion

Abstract

Localised corrosion is a cause of unanticipated and sometimes catastrophic failures of equipment, transport vessels and infrastructures. Therefore, the development of modern corrosion-resistant materials and inhibitors by design is both technically and economically attractive. In the coming decades, industrial components will be engineered from molecular structures. This prospect provides the designer with a truly enormous range of choices in design, which is a situation that demands predictive tools that can link molecular structures with the final component performance. In particular, the development of alloys and inhibitors can replace the use of toxic compounds in protecting metal surfaces. To execute a tailored design programme, it is necessary to understand how corrosion and the associated processes occur from the molecular level to the component level and how the overall system behaviour emerges because of the inherent links among different scales. Therefore, in the present work, the literature on theoretical modelling of localised corrosion and related experimentation are reviewed from a multiscale viewpoint. The review addresses (a) the challenges in the theoretical formulation of the important phenomena that influence localised corrosion and (b) the hurdles facing computational methods. It is shown that (i) the existing models lack the resolution to design effective corrosion-resistant systems, (ii) the numerical strategies for linking the scales are in a state of evolution and (iii) there are gaps in the experimental characterisation of the corrosion system, particularly at the lower end of the scales. Suggestions are provided towards the construction of a multiscale model (MSM) for localised corrosion.

Keywords:

• Localised corrosion
• Pitting corrosion
• Crevice corrosion
• Multiscale model
• Materials by design
• Density functional theory
• Inhibitors

The authors thank Prof. Rudy G. Buchheit (Fontana Corrosion Center, Ohio State University) who generously contributed to several discussions on topics of interest during his visit that was supported by a Fellowship from CSIRO and provided feedback on this manuscript. In addition, the authors would like to thank Dr Michael Breedon (CSIRO) for discussions on molecular modelling and DFT. Highly useful suggestions were provided by Drs Tony Cook (Manchester University) and Anton Kokalj (Jožef Stefan Institute) during their tenures as visiting scientists with CSIRO. This project was sponsored by the Advanced Materials Transformational Capability Platform (AMTCP) of CSIRO.