A Nanotech-barrier Coating To Reduce Tarnish on Silver Artwork

University materials scientists and museum art conservators collaborated to refine a metal oxide coating that uses nanotechnology to reduce tarnish and preserve silver artworks.

Tarnish--the corrosion of highly polished silver surfaces--is a monumental problem for art collections throughout the United States and the world. The development of a long-lasting barrier coating suitable for one-of-a-kind silver artifacts would significantly reduce the cost and labor associated with maintaining and preserving silver art.

The standard practice in art conservation to reduce silver corrosion is the tedious application of a solvent-based polymeric coating (nitrocellulose) on artwork (manually applied by spraying, brushing, dipping or a combination of these techniques). Large, 3-D shapes with protrusions and irregularities such as handles, feet and lips are challenging to uniformly coat. 

Additionally, polymer-based barrier coatings reduce the reaction of silver metal with tarnishing pollutants, but they only last 10 to 20 years.

Using a technique from nanotechnology called atomic layer deposition, scientists are refining an alternative preservation strategy in which they apply nanometer-thick films of metal oxide on silver to reduce corrosion. The coating's lifetime could be more than 100 years.

Next, researchers will explore whether the coating meets rigorous tests required by conservators for practical use in the art world, such as being easily transported, removed and stored.