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Electrochemical techniques are mainly known in the field of cultural heritage conservation as a tool for the elimination of corrosion layers or the removal of chlorides. However, these techniques are also a valuable tool for assessing the anti-corrosive efficiency of protective coatings. The aim of this study was to evaluate the performance of different coatings for their use in metallic heritage conservation using polarization resistance (R p) and electrochemical impedance spectroscopy (EIS). Carbon steel samples were prepared to simulate the surface composition and morphology of historic steel artefacts, and coated by a conservator-restorer following the common practices in conservation treatments. Three commercial organic coatings have been studied: a microcrystalline wax (Renaissance TM) and a methyl acrylate/ethyl methacrylate copolymer resin (Paraloid TM B-72) dissolved in acetone-both them commonly used in conservation and restoration treatments-and a ethylene copolymer wax emulsion in water (Poligen TM ES-91009), that has not been used so far for this purposes. Four commercial corrosion inhibitor additives were added to the Paraloid TM B-72 resin and Poligen TM ES-91009 wax. The additives were commercial preparations with the following known active components: a blend of triazoles (M435), an ammonium salt of tricarboxylic acid (M370), a calcium sulphonate (M109), and a bis-oxazoline (Alkaterge-T TM). R p and EIS results showed that the best protection of the steel specimens was afforded by Poligen TM ES-91009 when applied in thick layers. None of the additives have shown a clear improvement of the protection properties of the coatings, and one of them impaired the barrier effect of the coating.

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Fatal events taking place in World War (WW) I and II have left behind important historical evidence as an underwater cultural heritage (UCH) (e.g., shipwrecks, submerged aircraft, war artifacts), lying in peace at the bottom of, among others, the Mediterranean Sea. The article aims at exploring the challenges for UCH protection/preservation and sustainable exploitation with emphasis on this sea. UCH is so far dealt with in a “silo” approach by marine archaeologists or heritage professionals, who often ignore its potential for serving local sustainable development goals. The paper elaborates on the value, but also the complexity, multi- and inter-disciplinary as well as multi-actors’ nature of UCH management and sustainable exploitation, perceiving these as a “wicked” planning problem. It attempts to illuminate various important dimensions of this problem, such as its glocal (global/local) context; the conflicting and, in certain cases, inconsistent UCH legal protection framework, touching upon a variety of spatial scales; the contemporary policy frameworks favoring UCH management; etc. Exploration of these dimensions reveals open issues or gaps that need to be filled, and sets the ground for a more holistic and integrated UCH research and management approach for building up the yet largely untold, Mediterranean WW I and II UCH narrative; and shifting this area from a sea graveyard to a place of memory and cultural enrichment.