Cupro Nickel or CuNi or copper-nickel is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. The copper contents typically vary from 60 to 90 percent. CuNi is highly resistant to corrosion by salt water and is therefore used for piping, heat exchangers and condensers in seawater systems, as well as for marine hardware. They are also used in military equipment and chemical, petrochemical, and electrical industries.
Important properties of cupronickel alloys include inherent resistance to macrofouling, good tensile strength, corrosion resistance, excellent ductility when annealed, and thermal conductivity.