High temperature thermocouples that are used in reducing or vacuum environments are made using alloys from a group of rare elements called refractory metals. This is a class of metals with extraordinary resilience to wear, heat (melting point above 2000ºC) as well as to acid attack. For example, tungsten and rhenium are used for refractory metal thermocouples type C and D. Sheath material for these thermocouples can also include molybdenum, tantalum and platinum. They are used in extreme environments such as furnaces, rocket engines and ovens.
At Kamet, our years of experience in the extreme heat applications makes us well-positioned to advise you which combination of our refractory metal thermocouples and sheath materials will best suit your situation. You can call or email to get in touch with one of our advisors.