Advantages of N type thermocouple
● Performance of oxidation resistance is strong under high temperature, long-term stability is good. The selective oxidation of Cr and Si elements in the Nickel-Chromium’s positive electrode in k-type thermocouple causes uneven composition of the alloy and thermoelectromotive force drift. Increases the content of Cr and Si in N-type thermocouple, Make the oxidation mode of nickel-chromium alloy change from internal oxidation to external oxidation, so that the oxidation reaction only takes place on the surface.
● Short-term thermal cycle stability is good under low temperature, and inhibits magnetic transformation.
● Strong resistance to nuclear radiation. N-type thermocouple remove Mn and Co, which are easy to decay in k-type thermocouple, and further strengthens the ability of neutron irradiation resistance.
● In the range of 400~1300℃, the linearity of n-type thermocouple is better than that of K-type thermocouple.
Disadvantages of N-type thermocouple:
● Material of N-type thermocouple is harder than that of K-type thermocouple, it is more difficult to process.
● The price is relatively expensive. The thermal expansion coefficient of N-type thermocouple is 15% lower than that of stainless steel, so NiCrSi/NiSi alloy should be used for the sheath of N-type armored thermocouple. The nonlinear error is large in the range of -200~400℃.