Cupronickels

copper-based alloys containing nickel as the principal alloying element. Nickel and copper combine to form a continuous series of solid solutions. The addition of nickel to copper increases its strength and electrical resistance, reduces the temperature coefficient of electrical resistance, and causes a marked increase in corrosion resistance. Cupronickels lend themselves readily to hot and cold mechanical pressure working in the production of sheets, strips, wire, bars, pipes, and various stamped products.

A distinction is made between structural and electrotechnical cupronickels. Structural alloys are characterized by high corrosion resistance and an attractive silver color (for example, melchior and nickel silver). Electrotechnical alloys have high electrical resistance and a high thermoelectromotive force in couples with other metals. They are used in the manufacture of resistors, rheostats, and thermocouples; constantan and copel are examples of electrotechnical cupronickels. In spite of the shortage of nickel, cupronickels are widely used in electrical engineering and shipbuilding, in the manufacture of utensils and popular objets d’art, and in medicine and pyrometry because of their numerous valuable properties. I.I. NOVIKOV