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DOI	10.1029/2020JB020159
	Equation of State of hcp Fe-C-Si Alloys and the Effect of C Incorporation Mechanism on the Density of hcp Fe Alloys at 300 K
	Pamato M.G.; Li Y.; Antonangeli D.; Miozzi F.; Morard G.; Wood I.G.; Vočadlo L.; Brodholt J.P.; Mezouar M.
发表日期	2020
ISSN	21699313
卷号	125 期号:12
英文摘要	Si and C are cosmochemically abundant elements soluble in hcp Fe under pressure and temperature and could therefore be present in the Earth's inner core. While recent ab initio calculations suggest that the observed inner core density and velocities could be matched by an Fe-C-Si alloy, the combined effect of these two elements has only recently started to be investigated experimentally. We therefore carried out synchrotron X-ray diffraction measurements of an hcp Fe-C-Si alloy with 4 at% C and 3 at% Si, up to ∼150 GPa. Density functional theory calculations were also performed to examine different incorporation mechanisms. These calculations suggest interstitial C to be more stable than substitutional C below ~350 GPa. In our calculations, we also find that the lowest-energy incorporation mechanism in the investigated pressure range (60–400 GPa) is one where two C atoms occupy one atomic site; however, this is unlikely to be stable at high temperatures. Notably, substitutional C is observed to decrease the volume of the hcp Fe, while interstitial C increases it. This allows us to use experimental and theoretical equations of state to show unambiguously that C in the experimental hcp Fe-C-Si alloys is not substitutional, as is often assumed. This is crucial since assuming an incorrect incorporation mechanism in experiments leads to incorrect density determinations of ~4%, undermining attempts to estimate the concentration of C in the inner core. In addition, the agreement between our experiments and calculations supports Si and C as being light elements in the inner core. © 2020. American Geophysical Union. All Rights Reserved.
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187484
作者单位	Department of Earth Sciences, University College London, London, United Kingdom; Department of Geosciences, University of Padova, Padova, Italy; Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Paris, France; Dipartimento di Scienze della Terra, Università degli Studi di Milano, Milan, Italy; Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble, France; European Synchrotron Radiation Facility, Grenoble, France
推荐引用方式 GB/T 7714	Pamato M.G.,Li Y.,Antonangeli D.,et al. Equation of State of hcp Fe-C-Si Alloys and the Effect of C Incorporation Mechanism on the Density of hcp Fe Alloys at 300 K[J],2020,125(12).
APA	Pamato M.G..,Li Y..,Antonangeli D..,Miozzi F..,Morard G..,...&Mezouar M..(2020).Equation of State of hcp Fe-C-Si Alloys and the Effect of C Incorporation Mechanism on the Density of hcp Fe Alloys at 300 K.Journal of Geophysical Research: Solid Earth,125(12).
MLA	Pamato M.G.,et al."Equation of State of hcp Fe-C-Si Alloys and the Effect of C Incorporation Mechanism on the Density of hcp Fe Alloys at 300 K".Journal of Geophysical Research: Solid Earth 125.12(2020).