Towards a new method for coating heritage lead

Mark Dowsett,Michel De Keersmaecker,Dipanjan Banerjee,Annemie Adriaens,Simon Brown,Rosie A Grayburn

doi:10.1186/2050-7445-2-14

Abstract

BackgroundEthanolic solutions of long-chain carboxylic acids can be applied to lead metal substrates to form a coating of lead carboxylate which provides protection against atmospheric pollutants.Results and conclusionsIn this paper we describe the optimal inhibitor concentration for the coating on lead. Electrochemical impedance data taken before and after immersion in media modelling oak emitted volatile organic compounds (VOCs) polluted atmospheres show that coating effectiveness decreases after exposure, but the effect is lessened if longer chain carboxylates are used.

Highlights

Heritage metals are often coated as part of a conservation treatment to protect the metal surface from atmospheric deteriogens
Lead is of particular interest to conservation scientists due to its surface reactivity in air and its occurrence in reactive atmospheric environments such as within pipe organs [2], the proximity of volatile organic compounds (VOCs)-emitting oak to lead pipes creating the ideal conditions for corrosion
The solution can be applied to the surface by immersion or spraying, which makes it easy to use for large surface areas

Summary

Introduction

Heritage metals are often coated as part of a conservation treatment to protect the metal surface from atmospheric deteriogens. Common protective coatings used in conservation practice are paraffin and microcrystalline waxes [1]. Lead is of particular interest to conservation scientists due to its surface reactivity in air and its occurrence in reactive atmospheric environments such as within pipe organs [2], the proximity of VOC-emitting oak to lead pipes creating the ideal conditions for corrosion. Another similar example is the storage of small lead artefacts in wooden display cases. Electrochemical impedance data taken before and after immersion in media modelling oak emitted volatile organic compounds (VOCs) polluted atmospheres show that coating effectiveness decreases after exposure, but the effect is lessened if longer chain carboxylates are used.

Methods

Results

Conclusion