Copper Conductivity Materials

Introduction to the Copper Conductivity Materials Database

This section introduces coppers and copper alloys for conductivity 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. The graph on the right illustrates this for enhanced tensile strength.

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 conductivity material.

Alloy Selection Menu

Browse the 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.

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 (silver, tin and 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 (tin, magnesium, chromium, iron and 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 (tin, silver, chromium, zirconium and 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 coppers/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.

High Conductivity Copper for Electrical Engineering

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Copper base conductivity materials infographic
A simple infographic explaining the various properties and uses of copper and copper alloys for electrical and electronic applications. (Click to enlarge.)
Tensile Strength vs Electrical Conductivity
Tensile Strength vs Electrical Conductivity. (Click to enlarge.)
Effect of elements on copper's conductivity

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

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
N/mm2
Elongation
%
Hardness
HV
Thermal
Conductivity
W/moC
Machine
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
95
350
260
30
165
350
20
450
Copper-tellurium
CuTeP
 94 300  240  95  370  80
150 
Copper-sulphur
CuSP
 94 300  240  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
45
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
-
-
-
                 
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