Tarnish
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206784742
2008-04-19T23:28:13Z
Edward321
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rvv
'''Tarnish''' is a layer of [[corrosion]] that develops over [[copper]],
[[brass]], [[silver]], [[aluminum]] as well as a degree of semi-reactive metals as they undergo [[oxidation]]. It is analogous to [[rust]], but with a slower rate of occurrence. It is mainly caused by chemicals in the air such as [[sulfur]]. It appears as a grey or black film over the metal.
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===Chemistry===
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==Prevention==
{{Refimprove|date=September 2007}}
In objects which are primarily for display rather than use, the tarnishing process can be prevented in the long term by [[tinning]], a process by which the reactive substance is coated in a non-reactive substance, such as [[tin]] or [[wax]], and thus protected from oxygen.{{Fact|date=September 2007}}
For more frequently used items such as [[silverware]], tarnish is easily prevented by constant use and washing with a mild dish soap.{{Fact|date=September 2007}}
==Removal==
"This kitchen version of electrostripping is safe and easy. It's especially useful for removing tarnish from flatware and holloware. In a pot lined with aluminum foil, mix a diluted solution of equal parts of baking soda salt, and liquid soap. A quarter cup of each to a gallon of water is a typical mixture. Set the sterling in the pot; bring the mix to a simmer and allow it to stand for 10-20 minutes as the oxides are transferred to the aluminum, which you'll see is darkened. Throw that away and wash the silver before using it".<ref> (McCreight, Tim. ''The Complete Metalsmith''. Brynmorgen Press Inc., Portland, Maine. 2004.)</ref>
Another way to treat tarnish is to put a drop of water and some fluoride toothpaste on a tissue and rub it on the affected metal.{{Fact|date=September 2007}}
==References==
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[[Category:Chemical reactions]]
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