The effect of silicon impurities on the phase diagram of iron and possible implications for the Earth's core structure

Côté, Alexander S.; Vočadlo, Lidunka; Brodholt, John P.

doi:10.1016/j.jpcs.2008.03.031

Cited by 27 publications

(17 citation statements)

References 27 publications

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“…Sata et al (2008) found a new CsCl phase of FeS above 180 GPa using synchrotron X-ray diffraction techniques. 12); this was subsequently confirmed by ab initio simulations at zero Kelvin (Côté et al, 2008a). 12); this was subsequently confirmed by ab initio simulations at zero Kelvin (Côté et al, 2008a).…”

Section: The Effect Of Light Elements On the Stable Phase Of Iron In mentioning

confidence: 72%

New Frontiers in Integrated Solid Earth Sciences

Cloetingh¹,

Negendank²

2010

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The book series is dedicated to the United Nations International Year of Planet Earth. The aim of the Year is to raise worldwide public and political awareness of the vast (but often under-used) potential of Earth sciences for improving the quality of life and safeguarding the planet. Geoscientific knowledge can save lives and protect property if threatened by natural disasters. Such knowledge is also needed to sustainably satisfy the growing need for Earth's resources by more people. Earths scientists are ready to contribute to a safer, healthier and more prosperous society. IYPE aims to develop a new generation of such experts to find new resources and to develop land more sustainably.

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Section: The Effect Of Light Elements On the Stable Phase Of Iron In mentioning

confidence: 72%

New Frontiers in Integrated Solid Earth Sciences

Cloetingh¹,

Negendank²

2010

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“…It is well understood that solid Fe undergoes the phase transition near melting from bcc to fcc phase at 5.2 GPa. Despite the fact that the presence of Si stabilizes the bcc structure of Fe (Côté et al, ) and subsequently affects the behavior of the liquid, it does not explain the observed ρ along the melting line since Fe melting from a bcc structure shows decreasing ρ along the melting boundary. This suggests the existence of a more subtle mechanism that acts on the atomic scale and modulates the behavior of charge carriers as discussed later.…”

Section: Resultsmentioning

confidence: 98%

Heat Flow in Earth's Core From Invariant Electrical Resistivity of Fe‐Si on the Melting Boundary to 9 GPa: Do Light Elements Matter?

et al. 2019

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The electrical resistivity and thermal conductivity of liquid Fe alloys are the least constrained parameters in Earth's outer core (OC). These parameters are important as they modulate energy budget available for the geodynamo and affect the spatiotemporal evolution of the core. We report results of electrical resistivity measurements on solid and liquid Fe‐4.5 wt%Si from 3–9 GPa using a large volume multianvil press. The internally modified 18/11 octahedron cell was used to maintain the geometry of the liquid sample and to delay the onset of contamination. Electrical resistivity of solid Fe‐4.5Si decreases steadily with pressure and is very sensitive to increasing temperature‐driven onset of phase transitions. Along the melting boundary and within error, electrical resistivity remains constant and assumes the same value of 120 μΩcm as observed in pure liquid Fe. The results are interpreted in the context of icosahedral short‐range order (ISRO) structures that exhibit higher concentration with increasing pressure. Along the melting line, the increasing concentration of ISROs reduces charge carrier mean free path and prevents decrease of electrical resistivity with increasing pressure as seen in liquid metals, Cu, Ag, and Au, which do not have ISROs. In light of recent developments in understanding of the structure and dynamics of liquid transition metals and alloys, we postulate that our findings are applicable to other Fe alloys in the OC with small light element (C, S, and O) content. We calculated an adiabatic heat flow of 9.4–12 TW at the OC‐CMB interface, which admits thermal convection.

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“…It suggests a possibility of two-phase mixture in the inner core (Brosh et al, 2009;Fischer et al, 2013), although the boundary between hcp and hcp + B2 has never been constrained above 240 GPa. On the other hand, ab initio calculations argued that the incorporation of small amount of silicon in iron stabilizes body-centered cubic (bcc) or fcc phase with respect to the hcp phase (Vočadlo et al, 2003;Côté et al, 2008aCôté et al, , 2010, but it has never been verified by experiments. In this study, we examine the phase diagram and the equation of state (EoS) of Fe-Si alloys at multimegabar pressures by a combination of laser-heated diamond-anvil cell (DAC) techniques and synchrotron X-ray diffraction (XRD) measurements.…”

Section: Introductionmentioning

confidence: 99%