What is the highest temperature thermocouple?

This is actually not such a simple question as it seems! The reason being that even those thermocouples designed for extremely high temperatures have a maximum range that can be significantly affected by factors such as the;

• type and state of the product (liquid, solid, gas)
• environment (reducing/oxidizing/vacuum)
• type of thermocouple alloy and possible sheath material used
• diameter of the thermocouple wire and whether it is exposed or sheathed
• accuracy required
• variations in working temperature

However, generally speaking, refractory metal tungsten-rhenium thermocouples Type C and Type D are considered the highest temperature thermocouples, capable of being used for temperature measurement up to 2300ºC, provided it is not an oxidizing environment.

You can read more about thermocouples Type C (W5%Re-W26%Re) and Type D (W3%Re-W25%-Re), their differences and applications on our product page.

In an oxidizing environment the noble metal platinum-rhodium thermocouples Type R (Pt13%Rh-Pt), Type S (Pt10%Rh-Pt) and Type B (Pt30%Rh-Pt6%Rh) are considered the highest temperature thermocouples with a maximum range varying from 1400ºC up to 1700ºC.

Both the refractory metal and noble metal thermocouples are sometimes referred to as exotic thermocouples. You can read more about them on this page about exotic thermocouples and in our brochure.