Constantan Wire: A Key Material for Precision Measurement and Engineering

Constantan is an extraordinary copper-nickel alloy that has revolutionised various industrial and scientific applications. At Advent Research Materials, we supply Constantan exclusively in wire form, and its unique properties make it indispensable across numerous sectors. Discover why is it favoured by engineers, researchers and innovators around the world.

Constantan is an alloy primarily composed of copper (around 55%) and nickel (45%). Its defining feature is its consistent electrical resistivity, which remains stable over a wide range of temperatures. This reliability is essential in situations where temperature fluctuations occur, making Constantan a go-to material for precision measurement and control applications.

Constantan’s unique properties make it suitable for a variety of specialised uses, including; 

Thermocouples: A thermocouple is a type of temperature sensor that measures temperature by using the junction of two different metals. When these metals are joined together and exposed to heat, they produce a voltage that is directly related to the temperature difference between the hot junction (where the metals meet) and the cold junction (the other ends of the metals). This voltage can then be measured and converted into a temperature reading. Constantan is widely used in thermocouples, where it forms the negative leg of the device when paired with metals such as copper or iron. This allows for precise temperature measurement across industries like power generation, materials science and HVAC systems​

Precision Resistors: Constantan’s resistance to temperature change makes it ideal for use in wire-wound precision resistors, volume control devices and temperature-stable potentiometers (electrical devices used to measure or adjust voltage within a circuit). These are critical in applications where maintaining a stable resistance under varying conditions is essential​. 

Strain Gauges: Constantan is the material of choice for strain gauges used in civil engineering, industrial machinery, and even bridge construction. Its stability and sensitivity allow engineers to monitor stress and strain in structures, ensuring long-term safety and reliability​

Electrical Heating Elements: The melting point of constantan is approximately 1280°C! With its high heat resistance and ductility, Constantan is also used in electrical heating elements for heavy-duty industrial applications, such as in motor starters and rheostats.

The success of Constantan in these applications is largely due to its exceptional properties:

Stable Resistivity:  Constantan is known for its low thermal coefficient of resistance, which means its electrical resistance changes very little with temperature fluctuations. 

• Electrical Resistivity: Constantan has an electrical resistivity of approximately 49 µΩ·cm (micro-ohm centimetres) at 20°C​
• Temperature Coefficient of Resistance (TCR): Constantan's temperature coefficient of resistance is extremely low at about ±40 parts per million per degree Celsius (ppm/°C). This means that for each degree Celsius increase in temperature, the resistivity changes by only 40 ppm, making it very stable over a wide temperature range​
• Temperature Range: Constantan is effective over a broad temperature range, from -200°C to 600°C, and it maintains relatively stable resistivity throughout this range​.This makes it highly reliable in environments where temperature fluctuations are common, such as in industrial thermocouples.
• Seebeck Coefficient: When used in thermocouples (especially with copper), the Seebeck coefficient of Constantan is around -35 µV/°C when paired with copper. This value indicates how the voltage generated by the thermocouple changes with temperature​.

High Ductility: In wire form, Constantan is highly ductile, allowing it to be shaped or bent as required in complex setups or experimental designs.

Corrosion Resistance: Constantan's resistance to atmospheric corrosion makes it suitable for long-term use in harsh environments, such as industrial settings with moisture or chemicals.

At Advent Research Materials, we provide high-quality Constantan wire that meets the stringent demands of scientific research and industrial projects. Whether you need reliable temperature measurement or strain monitoring, our Constantan wire is designed to deliver precision and dependability.

For more information on Constantan and how it can be used in R&D for your next project, contact us today.