Properties Of Liquid Iron Research Articles

Ab Initio Molecular–Dynamics Study of Structural and Bonding Properties of Liquid Fe–Light–Element–O Systems Under High Pressure

The structural and bonding properties of liquid iron–light–element–oxygen ternary systems such as Fe–H–O, Fe–C–O, Fe–Si–O, and Fe–S–O under high pressure are studied by ab initio molecular dynamics simulations. H, C, O, Si, and S are the candidate light elements in the Earth’s outer core (liquid iron is a major constituent). From our simulations, it is found that H, C, and O show “interstitial” type behavior while Si and S show “substitutional” type behavior in the liquid iron–light–element–O ternary systems. For the interactions between light elements, C–C, Si–Si, and Si–O show covalent–like interactions even under high–pressure condition. The Si–O covalent bond causes a shift in the ionic charge of Si to more positive, which could be related to the immiscibility of liquid Fe–Si–O.

Properties of liquid iron along the melting line up to Earth-core pressures

We report a molecular dynamics study of the transport coefficients and the infinite frequency shear modulus of liquid iron at high temperatures and high pressures. We observe a simultaneous rise of both the shear viscosity and the diffusion coefficient along the melting line and estimate whether liquid iron can vitrify under Earth-core conditions. We show that in the conditions of the model studied in our work iron demonstrates a moderate increase of viscosity along the melting line. It is also demonstrated that at the limit of high temperatures and high pressures the liquid iron behaves similarly to the soft sphere system with exponent n ≈ 4.6.

Lattice dynamics analysis of the thermal properties of liquid iron

Abstract In this paper, the embedded atom method potential and Johnson potential are applied to calculate the thermal properties of liquid iron with an emphasis on a wide rage of temperatures and pressures. The results show that the liquid iron self-diffusion coefficient increases with increasing temperature and decreases with increasing pressure. The calculated self-diffusion coefficient is in good agreement with Protopapas' hard-sphere model at atmospheric pressure. According to the simulation results, we can get the Arrhenius equation between diffusion coefficient, temperature and activation energy. Increasing pressure enlarges the liquid iron activation energy and reduces the movement of atoms in liquid iron. Liquid iron thermal conductivity is computed using non-equilibrium molecular dynamics simulation and the simulation results are consistent with Pottlacher's experimental results with acceptable uncertainty in the 1535–2700 K temperature range.

Transport properties of liquid iron up to 6 Gpa

Abstract The electronic thermal conductivity λe(T, p) is determined by application of the Wiedemann-Frans relation with the Lorens function L(T) as obtained at 1 atmosphere, to electrical conductivity data obtained from two sets of high p, T measurements through the polymorphic phases into the liquid atate of pure Iron. Values of Δλe(T, p)/Δp in the liquid state vary between 42. 6 and 52. 4[mW cm−1 K−1 GPa−1].Contributions to variations of the Lorens number L(T, p) are discussed in terms of the density of levels Nd(C) and the changes of the Fermi energy ϵ with p, T as obtained from data on the thermoelectric power S(T, p) variations combined with the electrical conductivlty u(T, p) variations, both determined from high presaure experimental values for did and liquid iron.

Effect of temperature on the structure of liquid iron

Review of published data on the properties of liquid iron at different temperatures. Conclusion supporting a proposal that a structural change takes place in the melt.