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An interlaboratory comparison in the temperature range between −190 °C and 420 °C was organised between the National Institute of Quality, Normalisation and Industrial Quality (Inmetro), Brazil, and the Physikalisch Technische Bundesanstalt (PTB), Germany. This comparison followed the same protocol as the EUROMET project 552 comparison and was carried out in the years 2001-2002. A standard platinum resistance thermometer (SPRT) of 25 Ω was calibrated at the temperature fixed points of Ar, Hg, the triple point of water (TWP), Ga, In, Sn and Zn, with at least three realisations of each fixed point at both institutes. The uncertainty evaluation is given by Inmetro and some differences in the calibration procedures or in the measuring instruments used are described. The agreement between the results of laboratories was not in all cases within the combined uncertainties. Results of other comparisons are presented, which give additional information on the equivalence of the realised temperature scales.

The highest-temperature, defining fixed point of the International Temperature Scale of 1990 (ITS-90) is the copper freezing point (1,084.62 • C). Many international metrology institutes are investigating the use of transition temperatures of metal-carbon alloys as references for the calibration of temperature measuring instruments above the copper point, making it possible to reduce the calibration uncertainty of pyrometers in radiation thermometry and thermocouples in contact thermometry. This research is being performed mainly by radiation thermometry laboratories that have developed specific cells with blackbody cavities containing relatively small quantities of metal-carbon alloys. Parallel to this, some laboratories have also developed cells with these same alloys, but of a different design, suitable for the calibration of thermocouples. This report concerns the development of a nickel-carbon eutectic cell ( ∼ =1,329 • C) at Inmetro, with which either a radiation thermometer or thermocouple can be calibrated. The measurements of the temperature of this cell were performed using the reference radiation thermometer of the Pyrometry Laboratory and Pt/Pd thermocouples that were constructed, stabilized, and calibrated at the Thermometry Laboratory. Details of the cell fabrication, as well as the instrumentation used for the measurements are given. The results of a comparison between the two different types of measurement are reported, including the uncertainty budgets of both methods.

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