Passivation and Material Science: A tribute to Prof. Digby D. Macdonald…

Passivation is a key factor in the durability of materials. It presents an even more crucial challenge when we are faced with the challenges of environmental and climate transitions. These challenges require control and mastery of resources, sustainability and material manufacturing processes. In this context, the work of Prof. Digby D. Macdonald is both pioneering and important.

Today, it has inspired a great number of studies, and, when they are discussed, Digby D. Macdonald's research inspires many developments, attested to by the emergence of numerous models based on the renowned Point Defect Model.

Of course, this is not to reduce Prof. Digby D. Macdonald's work to passivation alone, but this presentation attempts to provide a brief overview of how his work, and that of his closest collaborator, Prof. Mirna Macdonald, has inspired me in my career as a corrosion specialist in particular and a materials scientist in general.

Beyond the mechanisms of passive film formation, the presentation will mainly focus on illustrating how the theme of passivation can enrich our knowledge of the role of additives on the one hand, and the conceptualisation of anti-corrosion solutions through the optimisation or definition of new materials, on the other hand.

The first topic will focus on the study of the effect of nitrogen on passivation and how the work carried out with Digby D. and Mirna Macdonald has led to an understanding of the so-called nitrogen blocking effect in the transport of passive films. The second example will focus on the strategy developed to develop new materials for the deployment of fuel cells for electromobility based on passive film functionalising. Finally, I will illustrate the various links between passivation and the multifunctionality of materials, based on recent work on tribocorrosion under irradiation.