Radiometric observation of melting and freezing plateaus for a series of metal-carbon eutectic points in the range 1330 °C to 1950 °C

Melting and freezing plateaus were radiometrically observed for the metal-carbon eutectics Ni-C, Pd-C, Pt-C, and Ru-C, using graphite crucibles and black-body cavities. The graphite crucibles were able to withstand heat cycles without breaking. Since the crucible material is a component of the eutectic fixed-point material, the latter is inherently free of contamination from the crucible. The temperature differences between the melting and freezing plateaus were generally less than 0.1 °C. The method seems to be a promising way of realizing a series of practical reference points above the copper point.