Hugoniot equation of state of cementite (Fe3C) up to 250 GPa and its geophysical implications

P-V-Tmeasurements of Fe3C to 117 GPa and 2100 K: Implications for stability of Fe3C phase at core conditions

“…At the P-T conditions above the solidus, our EoS gives slightly larger density than Hu et al (2019)'s data in partially or fully molten field, which is reasonable. A more recent shock wave experiment by Liu et al (2020) reported density data of Fe 3 C consistent with Hu et al, (2019) and therefore should be consistent with our EoS.…”

“…Our EoS for Fe 3 C is compared with reported volume data (Tateno et al 2010;Hu et al 2019;Liu et al 2020). which validates the applicability of our thermal EoS even at the inner core conditions.…”

“…GPa in a multi-anvil experiment and inferred from a shock compression experiment Hu et al 2019;Liu et al, 2020). In order to discuss the density of the core and the P-T location of reaction (1), a self-consistent thermal EoS for Fe 3 C should be established based on higher P-T experimental data.…”

Iron‐Carbon Alloy Under Shock Compression: Implications for the Carbon Concentration in Earth’s Inner Core

“…Our estimated carbon content also agrees with the results by first-principles calculations on the properties of C-doped hcp-Fe, where a 1-2.5 wt.% of C is suggested to match the density deficit of the inner core (Caracas, 2017). The carbon content proposed in the present study is ∼24% lower than some previous results (2.9(0.4) %) based on the equation of state of Fe 3 C by shockwave experiments (Hu et al, 2019;Liu et al, 2020). This discrepancy is most likely caused by the different crystal structures between the present Fe-C alloy (hcp) and Fe 3 C compound (orthorhombic; Hu et al, 2019) at high P-T conditions.…”

“…The lattice contributions to C V and γ eff are determined from C Vl = 3R/μ and γ l = γ 0 (ρ 0ε /ρ) q , respectively, where R and μ are the ideal gas constant and molar Red solid spheres represent the experimental results for the Fe-1.5wt.%C alloy. Open green triangles and inverted triangles represent Fe 3 C compounds (Hu et al, 2019;Liu et al, 2020), and open blue circles are iron (Brown et al, 2000). Errors are smaller than the symbol size.…”