MELTING POINT MAXIMA OF THC-THN AND OF UC-UN SOLID SOLUTIONS

Melting points of ThC-ThN and UC-UN mixtures in nitrogen atmospheres were determined. Maxima occur at 2910 ± 35°C with the compositions ThC0.35N0.65 ± 0.1 and UC0.3N0.7 ± 0.1. From a determination of the nitrogen activity the excess free energies of mixing the terminal mononitrides at 2820°C in the respective pseudo-binary solid solutions are inferred to be -3.2 ± 2.0 kcal/mole at the ThN mole fraction of 0.45 and -0.7 ± 1.5 kcal/mole at the UN mole fraction of 0.50. © 1969.