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Copper Alloys - Nickel Silvers

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Nickel silvers are alloys of copper, nickel (10 to 25%) and zinc (17 to 40%). While they contain no silver, they owe their name to the silvery luster they possess. The whitest alloys possess higher nickel contents.

Similar to brasses, depending on the actual composition, nickel silvers may be either single (alpha) phase or two-phase (alpha-beta). Nickel silvers are also known as nickel brasses.

Lead may be added to increase machinability, corrosion and wear resistance. However, this results in some loss of cold workability.

Key Properties of nickel silver are:

  • Good corrosion resistance
  • Excellent spring properties at elevated temperatures
  • Strength increases with nickel content with ductility remaining almost unchanged
  • Corrosion resistance increases with nickel content and is less susceptible to stress corrosion compared to copper-zinc alloys

Electrical conductivity is only a fraction of that of copper. Alpha alloys are ductile and can be easily worked at room temperature. Alpha-beta alloys cannot be worked at room temperature, but are easily hot worked

Applications

Electrical Contacts

Nickel silvers are used for electrical contacts in the electronics and telecommunications industries.

Gifts and Tableware

In this application, the items are often plated with silver. The item retains the luster even after the silver wears off owing to the natural color of the alloy and resistance to tarnishing. Thus to cut costs on silver, this alloy is used as the base-metal and silver metal is electroplated (E.P.N.S. Electroplated Nickel Silver).

Nickel Silver alloy is also used in a range of items, from musical instruments, decoration, and jewelry to zippers, model making, and fishing rods.

Mechanical Connectors

Due to the favorable strength properties and excellent corrosion resistance, nickel silvers are used for applications such as clips, rivets, screws, hinges, and locks.

Other Applications

Other applications include springs, instrument parts, architectural fittings, machined parts, decorative items, resistance wire, musical instrument wire, camera parts.

However, the prolonged use of nickel silver alloy in contact with food causes leaching of copper, leading to copper toxicity.

Sources and Further Reading

Article Updated on the 27th March, 2019.

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