Editing Plating (section)

=== Silver plating ===
{{about|the method of adding a thin layer of silver to an object|the Manhattan Project operation|Silverplate|section=yes}}
{{See also|Weighted sterling}}
[[File:KeilwerthAltoSax.JPG|thumb|right|A silver-plated [[alto saxophone]]]]
[[File:Zircon Bracelet.jpg|thumb|This bracelet has zircon gemstones. The metal is zinc alloy base with silver coating.]]
Silver plating has been used since the 18th century to provide cheaper versions of household items that would otherwise be made of solid silver, including [[cutlery]], vessels of various kinds, and candlesticks. In the UK the [[assay office]]s, and silver dealers and collectors, use the term "silver plate" for items made from solid silver, derived long before silver plating was invented from the Spanish word for silver "plata", seizures of silver from Spanish ships carrying silver from America being a large source of silver at the time. This can cause confusion when talking about silver items; plate or plated. In the UK it is illegal to describe silver-plated items as "silver". It is not illegal to describe silver-plated items as "silver plate", although this is ungrammatical.

The earliest form of silver plating was [[Sheffield Plate]], where thin sheets of silver are fused to a layer or core of base metal, but in the 19th century new methods of production (including electroplating) were introduced. [[Britannia metal]] is an alloy of tin, [[antimony]] and copper developed as a base metal for plating with silver.

Another method that can be used to apply a thin layer of silver to objects such as glass, is to place [[Tollens' reagent]] in a glass, add glucose/dextrose, and shake the bottle to promote the reaction.

{{block indent|left=1.5|1=AgNO<sub>3</sub> + KOH → AgOH + KNO<sub>3</sub>}}

{{block indent|left=1.5|1=AgOH + 2 NH<sub>3</sub> → [Ag(NH<sub>3</sub>)<sub>2</sub>]<sup>+</sup> + [OH]<sup>−</sup> (Note: see [[Tollens' reagent]])}}

{{block indent|left=1.5|1=[Ag(NH<sub>3</sub>)<sub>2</sub>]<sup>+</sup> + [OH]<sup>−</sup> + [[aldehyde]] (usually glucose/dextrose) → Ag + 2 NH<sub>3</sub> + H<sub>2</sub>O}}

For applications in electronics, silver is sometimes used for plating copper, as its [[electrical resistance]] is lower (see [[Electrical resistivity and conductivity#Resistivity and conductivity of various materials|Resistivity of various materials]]); more so at higher frequencies due to the [[skin effect]]. [[Variable capacitor]]s are considered of the highest quality when they have silver-plated plates. Similarly, silver-plated, or even solid silver cables, are prized in [[audiophile]] applications; however some experts consider that in practice the plating is often poorly implemented, making the result inferior to similarly priced copper cables.<ref>{{cite web|url=http://www.audioholics.com/education/cables/silver-saboteurs-are-silver-audio-cables-better|title=Silver Saboteurs - Are Silver Audio Cables Better?|author=Clint DeBoer|publisher=Audioholics|date=2009-07-23|access-date=2011-12-11|url-status=live|archive-url=https://web.archive.org/web/20120130211636/http://www.audioholics.com/education/cables/silver-saboteurs-are-silver-audio-cables-better|archive-date=2012-01-30}}</ref>

Care should be used for parts exposed to high [[humidity]] environments because in such environments, when the silver layer is porous or contains cracks, the underlying copper undergoes rapid [[galvanic corrosion]], flaking off the plating and exposing the copper itself; a process known as [[red plague (corrosion)|red plague]].  Silver plated copper maintained in a moisture-free environment will not undergo this type of corrosion.