Cupronickel alloys are widely used for marine applications due to their excellent resistance to seawater corrosion, low biofouling rates, and good fabricability. They have provided reliable service for decades while offering effective solutions to today's technological challenges addition of nickel to copper improves strength and corrosion resistance while allowing the alloy to remain ductile.

Alloy C72500: Developed by Bell Laboratories to solve issues of stress corrosion found in field parts. The alloy blends the strength of Phosphor Bronze and the Corrosion resistance of Nickel Silver without too much loss of electrical conductivity. A combination of very good fatigue strength and resistance to corrosion and tarnish have also made this alloy an excellent choice for other applications found in corrosive environments or applications requiring improved solderability.

Chemistry Typical

UNS# COPPER NICKEL LEAD IRON ZINC OTHER

C70600 Balance 9.0 - 10.0* 0.05 max 1.0 - 1.8 1.0 max 1.0 Mn max

C71500 Balance* 29.0 - 33.0 0.05 max 0.40 - 1.0 max 1.0 max 1.0 Mn max

C72500 Balance 8.5 - 10.5* 0.05 max 0.6 max 0.50 max | 1.8 - 2.8 Sn, 0.20 Mn max

Physical Properties

Typical Density: 0.321 - 0.323 lbs/in3, 8.88 - 8.94 g/cm3

Electrical Conductivity: (% IACS at 68° F 20°C, annealed): 4.6 - 11 %

Mean Coefficient of Thermal Expansion: µin/in-° F:

68 - 572 ° F: 8.5 - 9.2

Thermal Conductivity: BTU-in/hr-ft2-° F at 68 ° F: 17 - 31

Modulus of Elasticity: KSI

18 - 22 x 103 in tension

Applications

Cupronickels Alloys: Condensers; Evaporator and heat exchanger application; Ferrules; Applications where biofouling is a concern; Silver colored coinage.

Copper-Nickel-Tin Alloys: Relay springs; Switch springs; Lead frames; Telecommunication connectors