The Nickel Copper (Cu-Ni) alloys are single-phase throughout the full range of compositions and many standard alloys exist within this range, usually with small additions of other elements for special purposes.
The Cu-Ni alloys are ductile, can be hardened only by cold working, and have low temperature co-efficient of electrical resistance. The nickel content in these copper nickel alloys also enables them to retain their strength at elevated temperatures compared to copper alloys without nickel.
Due to their naturally occurring resistance to seawater corrosion and intrinsic biofouling properties copper-nickel alloys have long been widely used in the components of seawater systems. From offshore oil and gas platforms to power and desalination plants and from commercial shipping to naval shipping, copper-nickel fittings have performed superbly in a host of marine applications.
Due to the fact that the copper nickel alloy Copper 90/10 requires no surface protection and hence gives extra safety, this copper nickel alloy is being increasingly employed for brake and hydraulic suspension systems and cooling systems in cars and commercial vehicles.
The copper nickel alloys composed of copper with 25% nickel with 0.05-0.4% manganese is commonly used for the manufacture of coins, medals and other semi valuable applications.
Due to the very low temperature co-efficient of electrical resistivity, the copper nickel alloys composed of copper with 45% nickel alloy is used for resistance wire in high precision resistors. This property of copper nickel alloys allows the resistor to operate at almost exactly the same resistance regardless of temperature.