Properties Evaluation of Fe95-xSi5Nix Under the Earth's Inner-Core Conditions: Insight from the Ab-Initio Investigation

Abstract

In this article we investigate under the same Earth's core conditions, the structural, electronic, and transport properties of Fe-Si-Ni ternary alloys based on Fe and 5% of Si with various concentrations 0%, 15%, 25%, and 40% of element Ni, by means of First-principles calculations. Based on Functional Density Theory (DFT). The Local Density Approximation (LDA) also has been adopted for the potential exchange correlation. We perform the calculation of electronic property at 360 GPa using the software Akai-KKR (machikaneyama), which used the Korringa-Kohn-Rostoker method along with coherent potential approximation (KKR-CPA). Afterward, we calculate the electrical resistivity of impurities formed on the Kubo-Greenwood formula with the vertex correction using SPR-KKR code, which is based on the relativistic polarized spin method. Then, we model the thermal conductivity by electrical resistivity for both varying in the range of 320–360 GPa and 4500-6000k of pressure and temperature, respectively; according to the conditions of the Earth’s inner core ICB using Wiedemann-Franz law. Hence, our results suggest that 85–115 µΩ·cm at 0 K and 320–360 GPa, then 225–285 µΩ·cm at 4500–6000 K and 360 GPa for electrical resistivity, and then 45–55 W·m− 1·K− 1 at 4500–6000 K and 360 GPa of thermal conductivity of Earth’s inner core. Lastly, the thermal and compositional convection is one of the major factors of global magnetic field that is generated by geodynamo driven.

Thermal conductivity of iron and nickel during melting: Implication to Planetary liquid outer core

“…Recently Xu et al [27] computed κ to be 77±10 W m −1 K −1 at the Earth's outer core conditions considering both the electron-phonon (e-ph) and electronelectron (e-e) scattering contributions to electrical and thermal conductivity in solid hcp − iron. The thermal conductivity in the outer-inner core boundary on C, O, Si and S doped Fe + 10% Ni at a rate 30% ternary systems were calculated in the range of 105 -140 W m −1 K −1 very recently by Zidane et al [28]. The above study did not discuss about the Bloch-Gruneisen law in combination with Mathiessen's rule to describe the phononic contribution, however they claimed that upon consideration of the phononic contribution, the thermal conductivity will decrease.…”