What is a high temperature thermocouple and for which environments can this be used?

High temperature thermocouples are fully or semi assembled sensors for temperature measurements starting around 1000°C and up to 2200°C. Due to the insulation and exotic sheath materials these thermocouples can be used in extreme environments where base metal thermocouples are failing.  

In what environments are high temperatures thermocouples used? 

High temperature thermocouples are often used in extreme or hazardous environments. Examples are vacuum, inert, oxidizing and reducing atmospheres.  

For example, our thermocouples are used in vacuum furnaces or ovens up to 2200°C. In that case, a type C or D thermocouple can be used with a Tantalum sheath. This sheath material has recommended maximum temperature of 2200°C and is allowed in inert or vacuum environments. 

What are exotic sheath materials? 

For High temperature thermocouples we offer Inconel 600, Platina/Rhodium but also the more exotic sheaths like Molybdenum, Tantalum, Niobioum 1% Zirc or coated Molybdenum. These sheath materials are very suitable for challenging environments and high temperatures.

Each sheath material had its own characteristics and best use environments. Please consult this our overview.  

Sheath typeSymbolRecommended
Allowable environmentStandard
sheath diameter
in mm
Minimum bend
Inconel 600B1175°C1345°CInert, vacuum, oxidizing1, 1.6, 3.2, 4.8, 6.45 x diameter
Pt10%RhAH1550°C1850°CInert, oxidizing1, 1.5, 1.6, 2, 3, 3.25 x diameter
Pt20%RhAW1550°C1850°CInert, oxidizing1, 1.5, 1.6, 2, 3, 3.25 x diameter
TantalumN2200°C2995°CInert, vacuum, oxidizing1, 1.6, 3.210 x diameter
MolybdenumO2000°C2620°CInert, vacuum, reducing1.6, 3.2, 4.8, 6.4Not bendable
Niobioum 1% ZircOCR2000°C2495°CInert, oxidizing1.6, 3.210 x diameter
Coated MolybdenumAV1600°C2200°CInert, vacuum3.2, 6.4Not bendable