Constantan® Resistance Alloy Foil



Constantan is a copper-nickel alloy. It is manufactured under close control from electrolytic copper and pure nickel, and it is available in the form of a foil.



Density ρ

8.9 g/cm³ at 20 °C


Tensile strength Rm

480 MPa at 20 °C



Coefficient of thermal expansion α

1.45E-5 1/K at 200 °C

Melting point Tm

1225 - 1300 °C

Specific heat capacity cp

395 J/(kg·K) at 20 °C

Thermal conductivity λ

25.3 W/(m·K) at 100 °C


Electrical resistivity ρel

5.2E-7 Ω·m at 20 °C

Temperature coefficient of resistance αres

2E-5 1/K at 20 °C

Chemical properties


Weight %



55 %


45 %

Technological properties

Application areas

It is an ideal alloy for winding heavy-duty industrial rheostats and electric motor starter resistances. High specific resistance, together with good ductility and resistance to corrosion are all-important requirements in the category, and Constantans satisfies the most demanding specifications. It is commonly used as a thermocouple alloy, in conjunctions with copper up to 400 °C and with iron up to 800 °C. In addition, it is used in precision resistors, temperature stable potentiometer, volume control devices and strain gauges. In the resistor field, its high resistance and negligible temperature coefficient of resistance are its main attractions.

This material data has been provided by Goodfellow.

All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.