EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The concept of Preventive Conservation of cultural artefacts in museums and collections (e.g. statues, weapons, coins, etc.) is based on mitigation of the deterioration or damage due to material ageing as well as biological, mechanical and chemical degradation processes on-going over time. These changes of the materials have to be described in models and validated by experimental data [1]. For metal objects, changes of the surface and of the sub-surface domain, e.g. caused by oxidation and corrosion, are major factors that have to be considered. The exposure of copper alloys (bronze, brass) to certain environmental or atmospheric conditions can lead to accelerated degradation of the artefacts. The oxidation mechanism of copper is complex, including oxide islands formation and surface reconstruction. To predict and to mitigate long-term corrosion phenomena, comprehensive studies of surface morphology, composition and growth kinetics at early stages of the oxidation are needed.
In this contribution, we investigate structure and kinetics of the oxidation reaction occurring on the copper surface in humid air by performing reactive molecular dynamics simulations at 338K. The time-dependent radial distribution function is computed to describe the chemical atom surrounding. We also discuss the mechanism of copper interaction with humid air and the formation of an oxide film on the copper substrate. The interpretation of the present modelling results is supported by XPS experimental data and DFT-based calculation results. These numerical calculations for early stages of the kinetic process allow to capture physical phenomena accompanying copper oxidation in humid air which are important for the understanding of long-term corrosion phenomena.
The study was supported by European Union’s Horizon 2020 research and innovation programme under grant agreement No 814624 CollectionCare: Innovative and affordable service for the Preventive Conservation monitoring of individual Cultural Artefacts during display, storage, handling and transport.
Literature:
[1] https://www.collectioncare.eu