9:45 AM - 10:00 AM
[SIT27-03] Density of the Fe70S30 liquid at high pressure: constraints from the Clapeyron-Clausius relation
Keywords:density, Fe-S melt, high pressure
The eutectic temperature of the Fe-FeS binary system decreases up to 14 GPa and increases with pressure above 14 GPa. The slope of eutectic melting curve is related to the density change upon a fusion at the eutectic point via the Clapeyron-Clausius equation. We can yield constraints on density of Fe-S eutectic liquid just above the eutectic temperature at the invariant point from the densities of the eutectic solid mixtures of Fe + FeS and Fe + Fe3S2 , because liquid density is higher and lower than those of Fe + FeS and Fe + Fe3S2, respectively, around 14 GPa.
Recently, we determine the crystal structure of the (Fe,Ni)3S2 solid solutions by in-situ observation using synchrotron radiation. We evaluate the density of Fe3S2 at the eutectic point and calculated the densities of the eutectic solid mixtures. Then, we can set the constraint on the density of the Fe70S30 liquid to 6.93 ± 0.08 g/cm3 at 15 GPa and 1200 K. This is a fairly strict constraint, especially for a lower bound without any assumptions. We also discuss the equations of state of the Fe-S liquid in the presentation.
Reference: Urakawa et al., PEPI, in press (https://doi.org/10.1016/i.pepi.2018.01.007)