Preliminary study of the anti-corrosion performance of different protection systems applied to two World War II aluminium alloy archaeological objects with different surface finishes

This article looks at the conservation of historic aircraft from the Second World War, testing different coatings to protect their aluminium alloy structures from corrosion. Five different protective protection systems, including Paraloid¿ B72, wax, Dinitrol¿, Multi Matt Clear Lesonal¿ and carboxylates, were evaluated by being applied to artefacts from WWII aircraft wrecks, in particular a wing fragment from a Supermarine Spitfire and a propeller blade from a P38 Lightning, which presented different surface conditions. The protected objects were exposed to real-life conditions (uncontrolled indoor environment). Advanced analytical techniques such as electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FTIR), optical coherence tomography (OCT) and scanning electron microscopy (SEM) were used to characterize the evolution and effectiveness of the protection systems. The results showed different degrees of effectiveness for different coatings. Dinitrol¿ and Lesonal¿ demonstrated the best protective properties, forming thin but effective layers that enhance corrosion resistance. Carboxylates, on the other hand, proved ineffective, while Paraloid¿ B72 and wax were not very effective and unsuitable for objects with original paint residues

The authors would like to express their sincere gratitude to DRASSM (Département des recherches archéologiques subaquatiques et sous-marines - France), the ABSA 39–45 association for providing the objects studied in this paper and Patrick Atkinson for his contribution to the development of the hybrid OCT system at 1250 nm. We would also like to thank JPI-CH and IPERION single bond HS for their financial support. Results obtained within MOLAB Transnational Access Project EPHA (project leader Elodie Guilminot) within the EU H2020 Project IPERION HS, contract no. 871034 and conducted with the partial use of the facilities at Spanish, Italian, UK, and Polish nodes of the European Research Infrastructure for Heritage Science (E-RIHS).