Smart conservation methodology for the preservation of copper-based objects against the hazardous corrosion

“Bronze disease” is a very dangerous cyclic copper corrosion phenomenon which commonly develops after the discovery of the artefact. Therefore, in the cultural heritage field every object is inimitable and whatever loss is irreplaceable, causing a protective coating to be indispensable. Herein we studied the efficiency of a transparent, protective and reversible diamond-like carbon (DLC) coating, deposited by plasma enhanced chemical vapour deposition on copper based alloys, to enhance the corrosion resistance of archaeological artefacts. The nano-structured DLC film resulted in the formation of a structure that exhibits water repellent properties and can act as a barrier layer to corrosion. Exposure of copper based alloys, with and without the DLC coating, to an aggressive chemical environment led to a remarkable inhibition of corrosion only for the coated samples. Moreover the DLC film on the Cu-based substrate was shown to have no effect on the morphology of the surfaces indicating that surface appearance is not affected. Consequently DLC coatings open a pathway into the development of safe and tailored solutions in the ancient metals conservation field. Furthermore the use of DLC coatings can be extended for the protection of objects that do not belong to cultural heritage but may still be subject to corrosion.