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Tarnishing of silver, which is typically a blue/purple/black colour, is triggered by its reaction with elements such as sulphur, moisture, oxygen and chlorides.
Oxygen and Sulphur compounds in the atmosphere, such as sulphur dioxide, hydrogen sulphide gases and organic vapours, all contribute to the tarnishing process, which is also accelerated by other factors.
In addition to these naturally occurring accelerants, jewellery manufacturers themselves may inadvertently contribute to the tarnishing process.
OXFORD, England -- Oxford Advanced Surfaces Group Plc, the advanced materials company, announced that it has developed a 1nm thick, environmentally friendly Onto[R] coating that acts to protect silver against tarnishing.
The effect of atmospheric pollutants on the surface of exposed metals can result in the formation of a number of unwanted compounds causing tarnishing of the surface.
Potential applications include industrial, household and automotive lighting systems, silver conductors throughout the electronics industry and other applications where silver or other valuable metals need to be protected from tarnishing.
Argentium(TM) Sterling Silver builds and increases its tarnish resistance over time and has the ability to constantly regenerate its anti- tarnishing properties.
Tarnishing changes not only the appearance of silver, but also its electrical properties such as contact resistance and conductivity.
Additionally, May has indicated that it will continue to fulfill its lease obligations to operate each store until arrangements can be made to divest the location, alleviating concerns over potential dark anchor spaces tarnishing the general appeal and leas ability of the affected malls.