Iron-rich metallic liquids are mostly present in Earth's outer core, but dispersed metallic melts might also exist in small patches in the deep mantle due to the reducing nature of mantle with increasing depth. Although the properties of metallic melts are not my primary focus, I have been involved in some studies on determining the sound velocity and phase diagram of Fe-light element alloys (e.g., S, C, Si, O, H, P) system, which is the primary constitute of the cores of Earth, terrestrial planets and several rocky/icy satellites. The ultrasonic signals are very sensitive to melting, and combined with in-situ X-ray diffraction measurements, can be used to determine the melting relations for mantle and core materials. The pressure and temperature dependences of velocity can also be used to calculate the Grüneisen parameter, which controls the adiabatic temperature gradient in a melt layer. Compared to the liquidus of core materials, such information is critical to the understanding of the solidification regimes for planetary cores (e.g., snowing core or growing core).

Relevant Publications

Chantel, J., Jing, Z., Xu, M., Yu, T., & Wang, Y. (2018). Pressure Dependence of the Liquidus and Solidus Temperatures in the Fe-P Binary System Determined by In Situ Ultrasonics: Implications to the Solidification of Fe-P Liquids in Planetary Cores. Journal of Geophysical Research: Planets, 123(5), 1113-1124.

Jing, Z., Yu, T., Xu, M., Chantel, J., & Wang, Y. (2020). High-Pressure Sound Velocity Measurements of Liquids Using In Situ Ultrasonic Techniques in a Multi-anvil Apparatus. Minerals, 10(2), 126.