(Keynote) Passivity at High Resolution: Insight from the Surface Science Approach

Abstract

Passivity is a key property for the durable use of metals and alloys since it provides nanometer-thick, long-term self-protection against corrosion thanks to the formation at the surface of a self-healing oxide film, the passive film. High resolution insight into the mechanisms of self‐protection against corrosion of metals and alloys by oxide passive films can be achieved with a surface science approach, applying surface analytical methods to model solid/liquid interfaces corroding under well‐controlled conditions. This will be illustrated by several examples drawn from the research work performed over the years in the research group led by Philippe Marcus. The review will cover the nucleation and growth of 2D passive layers of adsorbed hydroxide ions, the nanostructure and atomic structure of 3D passive films, the dissolution mechanisms of passivated surfaces and structural aspects of localized corrosion initiation at the nanometer and sub‐nanometer scales. Recent progress made on the understanding of the mechanisms governing chromium enrichment in passive films formed on Cr-bearing alloys such as stainless steel will be highlighted with data on nucleation and growth of the surface oxide obtained at both space and time high resolution.Some of this research has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (ERC Advanced Grant No. 741123, Corrosion Initiation Mechanisms at the Nanometric and Atomic Scales: CIMNAS).