Copper-nickel alloy is also known as cupronickel, is a copper alloy with nickel as the main element. It includes copper-nickel binary alloys and nickel-copper alloys containing other alloys such as manganese, iron, zinc and aluminum. The element copper and nickel can solubilize with each other. When the content of nickel exceeds 16%, the metal surface appearance looks white as silver. The higher the nickel content, the whiter the color.
Cupronickel is widely used in shipbuilding, petroleum, chemical industry, construction, electric power, precision instruments, medical instruments, Musical Instruments, etc., because of its excellent corrosion resistance, and easy to be molded, processed and welded. Some cupronickel also has special electrical properties, which can be used to make resistance elements, thermocouple materials and compensation wires.
Industrial cupronickel is divided into structural cupronickel and electrical cupronickel. Structure cupronickel (C71520 etc.) with high mechanical properties, pressure machining properties and extremely high corrosion resistance, good weldability, heat and cold resistance, commonly used to manufacture high temperature and strong corrosive medium work parts and ship components. Electrical cupronickel has been used for precision resistance alloy duo to its good thermoelectric performance, high resistivity, low resistance temperature coefficient thermoelectric performance, is widely used in electrical instrument manufacturing.
Manganese-copper, Constantan with manganese instead of nickel (also called nickel-free manganese-copper-nickel, containing manganese 10.8-12.5%, aluminum 2.5-4.5% and iron 1.0-1.6%) are manganese white copper with different contents of manganese. Manganese-copper – nickel is a precision resistance alloy. These alloys have high resistivity and low resistivity temperature coefficients and are suitable for standard and precision resistance elements. It is used for manufacturing precision electrical instruments, rheostat, gauges, precision resistors, strain gauges and so on. Constantan have high thermoelectric potential and can also be used as thermocouple and compensation wire.