CUPRO-NICKELS

CUPRO-NICKELS:

  Cupro-nickels are alloys of copper and nickel. Copper and nickel, when melted together in any proportion are perfectly miscible and dissolve each other. When the alloy solidifies, the solubility continues forming a solid solution.

          Cupro-nickels are silvery white in color and have extremely good corrosion-resistance. They are extensively used for marine fittings. They also possess good strength, hardness and ductility (mechanical properties). Coins of rupee five are made of 75% copper and 25% nickel. However, another alloy containing 45% Ni and 55% copper is called "Constantine". Mangenine resistant wire with a very low temperature co-efficient of resistance, consist of 80% copper, 5% nickel and 15% of manganese.

          Nickel silver and German silver are ternary alloys of copper containing from 5 to 45% of zinc and from 5 to 30% of nickel. They have fair strength, good plasticity and low thermal conductivity. They are used extensively as the base metal on which silver is plated for table ware and for high grade plumbing and hardware. They are used for electrical wares and numerous fittings.