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Copper Alloys - Copper/Nickel Alloys

Chemical Formula

Cu/Ni Alloys

Topics Covered

Background

Key Properties

Applications

Sea Water Condensor Systems And Desalination Plants

Automotive Applications

Marine Applications

Coins

Resistance Wire

Thermocouples

Other Applications

Background

Sometimes called cupro-nickels, there exists a range of different copper nickel alloys that possess different properties and hence are suited to a range of different applications. Some of the better known copper nickel alloys include:

All copper nickel alloys consist of only one phase as the copper nickel binary system exhibits complete solid solubility.

Key Properties

Properties of copper nickel alloys vary with composition, however, some properties of copper nickel alloys are outlined below.

Copper-Nickel alloy Copper 90/10 and Copper 70/30

Copper rich alloys are:

The nickel content in these copper nickel alloys also enables them to retain their strength at elevated temperatures compared to copper alloys without nickel.

Applications of Copper Nickel alloys

Sea Water Condensor Systems And Desalination Plants

Due to the good resistance to sea water corrosion, the copper nickel alloy Copper 90/10 and copper nickel alloy Copper 70/30 are employed for sea water condenser systems and in desalination plants, as well as pipe work in chemical plants.

Automotive Applications

Due to the fact that the copper nickel alloy Copper 90/10 requires no surface protection and hence gives extra safety, this copper nickel alloy is being increasingly employed for brake and hydraulic suspension systems and cooling systems in cars and commercial vehicles.

Marine Applications

The good resistance to biofouling and sea water corrosion resistance of the copper nickel alloys, Copper 90/10 and Copper 70/30 alloys have lead to its use in applications such as cladding for ships' hulls, legs of oil rig platforms and sea water intake screens.

Coins

The copper nickel alloys composed of copper with 25% nickel with 0.05-0.4% manganese is commonly used for the manufacture of coins, medals and other semi valuable applications.

Resistance Wire

Due to the very low temperature co-efficient of electrical resistivity, the copper nickel alloys composed of copper with 45% nickel alloy is used for resistance wire in high precision resistors. This property of copper nickel alloys allows the resistor to operate at almost exactly the same resistance regardless of temperature.

Thermocouples

The copper nickel alloys composed of copper-45% nickel alloy is also used for thermocouples as it develops a high and uniform EMF when coupled with other metals such as copper and iron.

Other Applications

Copper nickel alloys are also used in cooling circuits, ammunition, sea water corrosion-resistant assemblies, condenser tubes.

Property Table of Copper Nickel Alloys

Material: Copper Alloys - Copper Nickel Alloys

Property Minimum Value (S.I.) Maximum Value (S.I.) Units (S.I.) Minimum Value (Imp.) Maximum Value (Imp.) Units (Imp.)
Atomic Volume (average) 0.0071 0.0073 m3/kmol 433.268 445.473 in3/kmol
Density 8.5 8.95 Mg/m3 530.638 558.731 lb/ft3
Energy Content 140 180 MJ/kg 15167.4 19501 kcal/lb
Bulk Modulus 130 170 GPa 18.8549 24.6564 106 psi
Compressive Strength 85 550 MPa 12.3282 79.7708 ksi
Ductility 0.03 0.44   0.03 0.44  
Elastic Limit 85 550 MPa 12.3282 79.7708 ksi
Endurance Limit 138 240 MPa 20.0152 34.809 ksi
Fracture Toughness 26 79 MPa.m1/2 23.6612 71.8937 ksi.in1/2
Hardness 580 1650 MPa 84.1219 239.312 ksi
Loss Coefficient 1.5e-005 0.00056   1.5e-005 0.00056  
Modulus of Rupture 85 550 MPa 12.3282 79.7708 ksi
Poisson's Ratio 0.34 0.35   0.34 0.35  
Shear Modulus 45 58 GPa 6.5267 8.41219 106 psi
Tensile Strength 267 624 MPa 38.7251 90.5036 ksi
Young's Modulus 120 156 GPa 17.4045 22.6259 106 psi
Glass Temperature     K     F
Latent Heat of Fusion 220 240 kJ/kg 94.5825 103.181 BTU/lb
Maximum Service Temperature 425 480 K 305.33 404.33 F
Melting Point 1384 1508 K 2031.53 2254.73 F
Minimum Service Temperature 0 0 K -459.67 -459.67 F
Specific Heat 384 386 J/kg.K 0.297162 0.298709 BTU/lb.F
Thermal Conductivity 19 66 W/m.K 35.5686 123.554 BTU.ft/h.ft2.F
Thermal Expansion 16 17 10-6/K 28.8 30.6 10-6/F
Breakdown Potential     MV/m     V/mil
Dielectric Constant            
Resistivity 11.7 36.3 10-8 ohm.m 11.7 36.3 10-8 ohm.m
Environmental Properties
Resistance Factors
1=Poor 5=Excellent
Flammability 5
Fresh Water 5
Organic Solvents 5
Oxidation at 500C 3
Sea Water 5
Strong Acid 2
Strong Alkalis 5
UV 5
Wear 5
Weak Acid 4
Weak Alkalis 5