Tarnish Process of Silver in Atmospheric Environments Containing Hydrogen Sulfide and Nitrogen Dioxide

摘要

Atmospheric corrosion results from a corrosive electrolyte on the surface produced by exposure of a material to relative humidity and air containing part per billion concentrations of pollutant gases, such as hydrogen chloride, hydrogen sulfide, sulfur dioxide, nitrogen dioxide and ozone. Silver exposed to an atmospheric environment containing sulfur species forms a tarnish film consisting of silver sulfide as a major corrosion product and silver chloride, silver oxide and silver sulfate. In a mixed gas environment containing oxidizing gas, such as oxygen or nitrogen dioxide, the reaction mechanism and the kinetic behavior were not clearly defined.