The properties of those elements (Au, Pd, Pt, Rh and Ir) potentially suitable for use in high-precision thermocouple
thermometry at high temperatures are reviewed. Included is a discussion of their oxidation behaviour, the potential
for contamination from their insulation and the effect of relative thermal expansion of the thermo-elements and of
the insulation that contains them. The requirements for initial high-temperature annealing, stress-relief annealing and
vacancy annealing are critically examined and recommendations are given. Thermoelectric stability data for the Au/Pt,
Pt/Pd and Au/Pd combinations are summarized and the need for further study is indicated. © 1998 Elsevier Science
Ltd. All rights reserved.