Local Structure and Density Measurement of Liquid Fe-S, Fe-C-S Alloys at Planetary Core Conditions

This work aims at measuring the liquid structure and density of liquid Fe-S and Fe-C-S alloys at Moon’s core conditions (4-6 GPa, 1300-2000 K) by combined in situ X-ray diffraction and absorption techniques in the Paris Edinburgh cell (PEC). Specifically, the liquid structure will be investigated by angle-dispersive X-ray diffraction, while density will be extracted by the quantitative analysis of both liquid structure and absorption profile. The density obtained by both methods will be compared to verify the robustness of density extracted from liquid structure analysis. Ultimately, a complete density dataset of liquid iron alloys will be established and used to refine thermodynamic solution models based on the mixing properties of end-members and to model Moon’s core density as a function of its composition.