(Olin Palladium Award of the Electrochemical Society Address) Corrosion Mechanisms at the Atomic or Nanometric Scale

Tuesday, 3 October 2017: 18:10
Maryland B (Gaylord National Resort and Convention Center)
P. Marcus (Chimie-ParisTech, IRCP/PCS)
In this Award Lecture I will emphasize a surface science approach that allows to reach a deep understanding of the mechanisms of corrosion at the atomic or nanometric scale. I will show the link between atomic/nanometric scale mechanisms and the macroscopic corrosion manifestations. The lecture will include the combined experimental approaches using advanced surface analytical and electrochemical methods with theoretical approaches based on atomistic modeling.

The high resolution techniques used in combination with classical electrochemical methods will be presented, high resolution meaning high space resolution, as achieved by near field microscopies (Scanning Tunneling Microscopy and Atomic Force Microscopy), high energy resolution in electron spectroscopy for chemical analysis, and high mass resolution for surface molecular analysis by Time-of-Flight Secondary Ions Mass Spectrometry.

The formation of the metal-water interface occurring when a metal surface is exposed to water, which has been investigated by in situ Scanning Tunneling Microscopy, will be presented.

A major part of this address will be devoted to passivity of metals and alloys, a central issue in corrosion science and engineering since the formation of ultra-thin surface oxide films is the best of all means for protection of metallic materials against corrosion. I will discuss the growth mechanisms, the nanostructure, and the electronic properties of passive films, as well as passivity breakdown and initiation of localized corrosion, with emphasis on atomic and nanoscale data.

Cathodic reactions on oxidized metal surfaces will then be discussed, with a theoretical approach of the di-oxygen reduction on surface oxide films on Al surfaces using DFT.

Finally I will mention recent work on corrosion inhibition by adsorbed organic molecules, an area in which progress has been recently achieved by combining quantum chemical calculations (DFT) with experiments.