These 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 white colour 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).
Lead may be added to increase machinability but results in some loss of cold workability.
• 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 are 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
Nickel silvers are used for electrical contacts in the electronics and telecommunications industries.
Gift And Tablewares
In this application, the items are often plated with silver. The natural colour and resistance of this alloy to tarnishing means that even when the silver wears off, the item still retains an attractive appearance.
Due to the favourable strength properties and excellent corrosion resistance, nickel silvers are used for applications such as clips, rivets, screws, hinges and locks.
Other applications include springs, instrument parts, architectural fittings, machined parts, decorative items, resistance wire, musical instrument wire, camera parts.
Primary author: Dr. Agnes Sagal
Source: Materials Information Service, “Using copper and copper alloys” edited by Justin Furness, printed by The Institute of Materials.
For more information on this source please visit http://www.iom3.org/