Conductivity Materials

Introduction to the Copper Conductivity Materials Database

This section introduces copper conductivity materials (coppers and copper alloys) for electrical applications and provides details of properties and uses.

Copper has the highest conductivity of any non-precious metal. This, combined with its high ductility, good machinability, high strength, ease of jointing and good resistance to corrosion, makes copper the first choice as a conductor for electrical applications.

High conductivity copper is the most common form of the metal and it is widely available with consistent high quality. It is the first choice for the manufacture of bulk conductors such as cables, busbars, transformer windings and motor stators and rotors. However, for other electrical applications, such as connector parts, commutators and catenary wires, the mechanical properties may need to be enhanced by the addition of appropriate alloying elements. The ease with which copper can form alloys with other elements results in the availability of a very wide range of materials suitable for the full range of electrical applications.

As mechanical properties are enhanced by the addition of alloying elements, there is a trade off with a reduction in electrical conductivity.

Walk through of an infographic explaining the various properties and uses of copper conductivity materials for electrical and electronic applications

See infographic here.

The graph below shows how the addition of various alloying elements affects the conductivity of  copper.

Effect of various elements (impurities or intentional additions) on the conductivity of copper.
Effect of various elements (impurities or intentional additions) on the conductivity of copper. (Click to enlarge.)

This graph plots tensile strength and conductivity for different copper alloys.

Tensile Strength vs Electrical Conductivity of Copper/Copper Alloys
Tensile Strength vs Electrical Conductivity. (Click to enlarge.)

A downloadable reference publication, High Conductivity Copper for Electrical Engineering (Publication 122) describes the electrical and mechanical properties of high conductivity copper and copper alloys that are intended for use in electrical applications. It is primarily aimed at electrical engineers rather than metallurgists, but gives the basic metallurgical detail needed to understand the processing requirements of alloys.

The content in this section serves as an introduction to each copper conductivity material.

Copper Conductivity Material Selection Menu

Browse the coppers and copper alloys below, grouped by property, or use the Alloy Properties Table to link to information on individual alloys, including specifications, mechanical and physical properties, available product forms and applications.

Go to Copper Conductivity Materials Properties Table

Very High Conductivity

The standard copper for conducting electricity via wire, cables and busbars, with 100% IACS, is Cu-ETP. For special applications, such as vacuum, Cu-OF is used. Very small additions of alloying elements (e.g. silver, tin, tellurium) increase softening resistance at the expense of conductivity, whilst Cu-C offers a high conductivity (98% IACS) cast option. The coppers listed here have a minimum conductivity of 98% IACS.

High Conductivity + High Tensile Strength

Small additions of alloying elements (e.g. tin, magnesium, chromium, iron, zirconium) increase the strength of copper at the expense of conductivity. Applications include overhead grooved contact wires for trams and railways and high duty power cables. The coppers listed in this section have a minimum conductivity of 64% IACS and a minimum tensile strength of 460 N/mm2.

High to Very High Conductivity + Resistance to Softening

Small additions of alloying elements (e.g. tin, silver, chromium, zirconium, iron) increase the softening resistance of copper at the expense of conductivity. Applications include electric motors, generators, power cables and welding electrodes which run at high temperatures, whilst requiring excellent conductivity. Coppers in this section have a conductivity ranging from 64–100% IACS and a temperature limit minimum of 250°C.

High Conductivity + Resistance to Softening + High Tensile Strength

A small addition of iron gives the best combination of resistance to softening, strength and conductivity. The main application of this alloy is in leadframes. This copper has a conductivity of 90% IACS, a temperature limit of 360°C and a tensile strength of 500 N/mm2.

Good to High Conductivity + High Tensile Strength

The addition of small amounts of beryllium, nickel and silicon give heat treatable alloys of very high strength with good conductivity. Applications include contact springs, switchgear and stressed automobile components. These alloys also have the highest fatigue strength. The copper alloys in this section have a conductivity ranging from 44-98% IACS and a minimum tensile strength of 500N/mm2.

High Conductivity + Good Machinability

Additions of tellurium or sulphur to copper provide free machining properties needed for high precision CNC machining of components such as semi-conductor mounts, vacuum interrupters, plasma nozzles and resistance welding tips. These coppers range in conductivity from 64–98% IACS and have a minimum machinability index of 80%.

High Hardness

For components such as press-fit pins and contact springs, high strength and hardness with good conductivity is given by copper-nickel-silicon and copper-beryllium. These alloys range in conductivity from 45–60% IACS and have a minimum hardness of 220 HV.

Very High Conductivity + Good Castability

For complex shapes such as electrical switch gear which cannot be made by the use of wrought alloys, cast copper with a conductivity of up to 98% IACS may be used.

Low Conductivity + Excellent Castabilty

These brasses are much easier to cast for heavy duty components which only require low conductivity. They have conductivities in the region of 20% IACS.

Low Conductivity + Excellent Machinability

This leaded brass has the best machinability of any metallic alloy and offers a more cost-effective solution when only low conductivity is required. It has a conductivity of 22% IACS and a machinability index of 100%.

Low to Good Conductivity

The binary copper-zinc brasses are a cost effective choice for electrical applications which require a low (28% IACS) to good (56% IACS) electrical conductivity.

Alloy Properties Table

Indicative values are given in the table below for the most important mechanical and physical properties. Alloys are ordered in decreasing electrical conductivity. Click the alloy’s ISO designation to go to further information.

Alloy % IACS %Tensile Strength N/mm2 Proof Strength Elongation % Hardness HV Thermal Conductivity
W/moC
Index % Temp. Limit oC
Oxygen-free High Conductivity Copper
Cu-OF
Cu-OFE
102 385 325 60 115 394 20 130
Electrolytic Tough Pitch Copper
Cu-ETP1
101 385 325 55 155 394 20 130
Electrolytic Tough Pitch Copper
Cu-ETP
100 385 325 55 155 394 20 130
Oxygen-free Extra Low Phosphorus Copper
Cu-PHC
100 385 325 55 155 390 20 130
Silver-bearing Tough Pitch Copper
CuAg0.04
CuAg0.10
100 385 325 55 155 394 20 250
Silver-bearing Oxygen-free Copper
CuAg0.04(OF)
CuAg0.10(OF)
100 385 325 55 155 394 20 250
Copper-tin-tellurium
CuSn0.15Te
98 400 30 140 390 20 400
Phosphorus Deoxidised Tough Pitch Copper
Cu-DLP
98 385 325 55 155 365 20 130
Cast Copper
Cu-C
98 150 40 25 40 372 10 150
Copper-zirconium
CuZr
98 150 40 25 40 372 10 150
Copper-tellurium
CuTeP
 94 300 240 5 95 370 80 150
Copper-sulphur
CuSP
 94 300 240 5 95 347 80 150
Copper-iron
CuFe0.1P
90 520 480 15 160 364 18 200
Copper-tin
CuSn0.15
88 460 410 25 200 360 20 220
Copper-tin
CuSn0.2
83 620 30 290 20 220
Copper-magnesium
CuMg0.2
82 460 370 10 310 20 150
Copper-chromium-zirconium
CuCr1Zr
80 540 440 35 175 300 30 500
Copper-iron-phosphorus-magnesium
CuFePMg
80 552 490 15 190 320 20 150
Copper-tin
CuSn0.5
70 460 250 9 110 360 20 220
Copper-iron
CuFe2P
65 580 485 10 170 265 25 200
Copper-magnesium
CuMg0.5
64 520 430 10 270 20 150
Copper-beryllium
CuCo1Ni1Be
63 750 650 25 290 260 30 177
Copper-nickel-silicon
CuNi1Si
60 590 570 30 220 260 30 200
Copper-beryllium
CuCo2Be
60 750 650 20 290 199 30 177
Copper-beryllium
CuNi2Be
60 750 650 20 290 242 30 177
Copper-zinc
CuZn5
56 350 200 45 95 233 25 75
Copper-nickel-silicon
CuNi2Si
51 700 620 35 220 250 30 200
Copper-iron
CuFePCoSn
50 670 650 26 190 200 18 350
Copper-nickel-silicon
CuNi3Si
45 800 780 30 230 190 30 200
Copper-zinc
CuZn10
44 380 280 45 100 190 25 75
Copper-zinc
CuZn20
32 370 320 46 105 140 25 75
Copper-zinc
CuZn39Pb3
29 500 350 20 135 121 100
Copper-zinc
CuZn30
28 460 310 45 125 120 30 75
Copper-zinc
CuZn35Mn2Al1Fe1-C (Cast)
22 500 200 18 120 87
Copper-zinc
CuZn33Pb2-C (Cast)
20 180 70 12 50
Copper-zinc
CuZn39Pb1Al-C (Cast)
18 280 120 10 70