The Nicrosil versus Nisil thermocouple: Properties and thermoelectric reference data

In the formulation of the new alloys, the main method was to use basic thermodynamic data to predict the conditions of solute concentration, temperature and oxygen pressure under which certain discrete oxide layers could form on the surface as highly efficacious passivating films. This work was the culmination of extensive research in which thermoelectric instability in existing nickel-base thermocouple alloys was correlated with their physical, chemical and metallurgical properties. The basic thermoelectric properties of Nicrosil and Nisil were the subject of a joint research project between NBS and MRL. The aim of this project was to establish a body of standard reference data on the thermoelectric and other properties of the new thermocouple alloys which could be recognized by various standards authorities around the world.