Nicrsi-NisiMg (Type N) thermocouple is the latest base metal thermocouple, developed to improve the drawbacks that type K thermocouple has. The main chemical composition of positive leg Nicrsi (NP) is Ni: Cr: Si≈84.4: 14.2: 1.4; negative leg NisiMg (NN) is Ni: Si: Mg≈95.5: 4.4: 0.1. Type N thermocouple also be used in the similar atmospheres that type K works, and the operating temperature range is -200~1300℃.