# Stainless Steel Surface Structure and Initial Oxidation at Nanometric and Atomic Scales

## TL;DR

This study uses scanning tunneling microscopy to explore the atomic-scale surface structure and initial oxidation processes of stainless steel, revealing complex surface features and mechanisms critical for enhancing corrosion resistance.

## Contribution

It provides new atomic-scale insights into the initial oxidation mechanisms and surface modifications of stainless steel, advancing understanding of passive film stability.

## Key findings

- Reconstructed atomic lattice with self-organized vacancy lines.
- Initial oxidation involves step and vacancy mechanisms leading to Cr-rich oxide formation.
- Surface structure influences the stability and composition of the passive oxide film.

## Abstract

The durability of passivable metals and alloys is often limited by the stability of the surface oxide film, the passive film, providing self-protection against corrosion in aggressive environments. Improving this stability requires to develop a deeper understanding of the surface structure and initial surface reactivity at the nanometric or atomic scale. In this work we applied scanning tunneling microscopy to unravel the surface structure of a model stainless steel surface in the metallic state and its local modifications induced by initial reaction in dioxygen gas. The results show a rich and complex structure of the oxide-free surface with reconstructed atomic lattice and self-organized lines of surface vacancies at equilibrium. New insight is brought into the mechanisms of initial oxidation at steps and vacancy injection on terraces leading to Cr-rich oxide nuclei and locally Cr-depleted terraces, impacting the subsequent mechanism of chromium enrichment essential to the stability of the surface oxide.

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Source: https://tomesphere.com/paper/1907.10911