EMF changes of Pt/Pd thermocouples in the range from 420/spl deg/C to 1080/spl deg/C

Drifts in EMF of Pt/Pd thermocouples at Cu, Ag, Al and Zn freezing points were measured. Different heat treatments were applied to thermocouples before the calibrations. The measured results showed that large emf changes appeared at Cu and Ag freezing points, and the magnitude of the drift and inhomogeneity were dependent on the final step of the heat treatment method.