REVIEW OF METAL-CARBON EUTECTIC TEMPERATURES: PROPOSAL FOR NEW ITS-90 SECONDARY POINTS

摘要

This paper presents the results obtained on metal-carbon eutectic points in several NMIs which have initiated studies on these novel high temperature fixed points. From the first realisations performed by Y. Yamada at NMIJ [1] to the latest ones, that have gone through inter-NMI comparisons, the status of these high temperature fixed points has evolved to allow them today to be considered as potential fixed points in a future scale. Some general features of these particular points are brought to mind in this paper in order to understand someof the most important parameters that can affect their construction and implementation. After only five years of research, yielding an impressive amount of results and comparisons, M?-C eutectic fixed points can apply today for the status of secondary reference points, given the reproducibility and stability they have already shown. So, the best defined eutectic points are selected, upon clear criteria, andsubmitted to the CCT Working Group 2, in charge of the secondary points and techniques for approximation to the international temperature scale, to be adopted in the high temperature range. We believe this is only a first step that would allow them to be widespread, further studied and more accurately known in the perspective of the forth coming ITS-XX.