|MICC Sheath types||UNS Ref.||DIN Ref.|
Nicrobell is a nickel-chromium alloy with 1.4% of silicon which provides high oxidation resistance and strength at temperatures up to 1250°C.
The similarity of chemical composition of Nicrobell sheath and type N conductors reduces the potential for the diffusion of elements between the alloys resulting in reduced change in EMF output. The lack of Manganese and Aluminium in Nicrobell and type N alloys also prevents cross contamination of the thermocouple legs and subsequent thermocouple degradation over time. This ensures better stability of EMF output of thermocouples type N in Nicrobell compared to type K in 310 stainless steel sheath
Nicrobell also has good resistance and exhibits freedom from microstructural degradation in nitrogen based atmospheres due to absence of such alloying elements as Niobium or Aluminium, that form internal nitrides. This reduces risks of thermocouple failure due to the sheath embrittlement caused by nitridation.
Nicrobell® is a trademark of MICC Ltd, it is fundamentally the same specification as the formally made by Tyco Pyrosil material.