Testing New Coating Systems for the Long-Term Protection of Copper and Iron Alloy Collections Exposed in Uncontrolled Museum Environment

This paper discusses the evaluation of environmental friendly coatings and systems designed for the long-term protection of metal objects in museums. The study primarily focuses on the enhancement of Paraloid B72 by incorporating corrosion inhibitor additives, seeking to improve its protective capabilities. A series of six coating systems was tested on corroded copper and iron alloy coupons through accelerated aging within a climatic chamber. The performance evaluation utilized visual examination, scanning electron microscopy (SEM), and colorimetric analysis. Results varied based on the metal types, revealing that Poligen ES 91009, a liquid wax from BASF, offered superior protection for iron alloy coupons in comparison to Paraloid B72, whereas the protective efficacy for copper alloy coupons was consistently similar across all coatings. This research is conducted as part of a European project focused on metal conservation and highlights the critical need for effective coating solutions in the preservation of museum collections subjected to uncontrolled environments.