A new barrier coating to reduce tarnish on silver art

Glenn Gates, Eric Breitung, Terry Drayman-Weisser, Amy Marquardt, and Raymond Phaneuf

Abstract

The corrosion, or tarnishing of silver artifacts, especially polished silver surfaces, is a problem for art collections worldwide. We present results concerning the development of a novel, transparent barrier-coating for silver art using a technique known as “atomic layer deposition” (ALD), which allows for the creation of nanometer thick layers of metal oxides with an exquisite level of control, literally at the atomic level. The resulting transparent barrier coatings are optimized to reduce the rate of silver corrosion, and following the removal of the barrier coating, the silver is re-treatable. As with any treatment, the conservator must decide under what circumstances this treatment is appropriate. The specific focus of this research is a barrier coating based on amorphous aluminum oxide that is less than 100nm thick. Actual silver objects will be presented at this forum, using museum-facsimile illumination, and we seek feedback from participants regarding the visual characteristics of ALD-treatment, compared to traditional cellulose nitrate treatment and untreated silver. This critical evaluation by the conservation community is a central goal of our National Science Foundation Award 1041803.