Depression of the freezing point of lithium by nitrogen and by hydrogen. Eutectic Compositions and Solid Solubilities

Abstract

The depressions of the freezing point of lithium (gettered by yttrium at 400°C) caused by nitrogen and hydrogen have been determined by thermal analysis. For Li₃N in lithium, the freezing point drops progressively from 180.49 to 180.24°C at the eutectic composition, 0.068 mol % N. For LiH, the maximum depression is 0.08°C and the eutectic composition is 0.016 mol % H. The depression was used to calculate the solid solubility of N and H in lithium. For the liquid, the solubility of non-metal rises from the eutectic point to 0.070 and 0.017 mol % N and H, respectively, at the melting point, 180.49°C. The data complete the metal-rich end of the lithium-lithium salt phase diagrams.