Why is the manufacturing process for type C thermocouples wires so difficult?

Type C thermocouples have the unique advantage that they allow for extremely high temperature measurement with excellent accuracy (up to 2300Ā°C). They are suitable for applications in vacuum, high purity hydrogen, or pure inert atmospheres. However, it is essential to note that this thermocouple possesses inherent brittleness, and thus can be very challenging to work with. In addition, the manufacturing process for type C thermocouple wires is considered challenging due to the following factors.

Junctioning of the type C thermocouple wires

One significant difficulty lies in the junctioning process, where extreme care is required to prevent wire damage. Incorrect handling can lead to wire burning or oxidation, which could impact the thermocouple’s performance and reliability. Furthermore, there is the issue of the ductility and recrystallization temperature increase towards the positive type C electrode due to the addition of rhenium. Rhenium is necessary to reduce the issue of brittleness.

Cutting the type C thermocouple wires to required lengths

Cutting type C thermocouple wire to the necessary length presents another challenge. Standard cutting methods are inadequate as they may cause the wire to split, necessitating the use of special cutters to ensure precise and accurate cuts.


There are strict cleanliness requirements during assembly of type C thermocouples and this adds to the complexity. To ensure the highest quality, all our ARi high-temperature type C thermocouples are assembled in a cleanroom environment.

Due to the complexities involved and the potential risks in producing type C thermocouples, some manufacturers have type C production. To produce a high quality, reliable and accurate type C product also requires significant investment in the necessary equipment and trained personnel.

At Kamet we work closely in a long-standing relationship with the top-class manufacturer ARi. ARi has been an innovative market leader in thermocouple production since the very early days of development in the 1950s. Thanks to our partnership, we are able to also offer various Type C customization options, for example in sheath materials.

For more technical information and specifications on our exotic thermocouples with type C wire you can access our brochure. Should you have any specific questions, please contact us and one of our experts will be happy to help you.