New Strategy for Corrosion Inhibition Coatings for Lead Heritage Metal Objects

Abstract

Corrosion is the major problem in the degradation of heritage metal objects. The development of appropriate treatment methods to stabilize and protect artefacts is a undeniable scientific challenge. Here we propose a new coating method to protect lead heritage metal objects. This coating is environmentally safe, stable, reversible, easy to apply and to remove, and aesthetically justified. The coating consists of a compact and thick layer of lead ditetradecanoate, which is formed upon immersion of a lead substrate in a melted sample of tetradecanoic acid at 60oC. Coated lead samples were exposed either to an aqueous corrosive environment or to a closed chamber with high relative humidity and an oak corrosive atmosphere. The corrosion resistance of the coating was followed for 60 days by electrochemical impedance spectroscopy and X-ray diffraction. Results show an unprecedented corrosion inhibition of the new coatings.