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Compositional effects in the liquid Fe–Ni–C system at high pressure

DOI zum Zitieren der Version auf EPub Bayreuth:
URN to cite this document: urn:nbn:de:bvb:703-epub-7028-3

Title data

Posner, Esther ; Steinle-Neumann, Gerd:
Compositional effects in the liquid Fe–Ni–C system at high pressure.
In: Physics and Chemistry of Minerals. Vol. 49 (2022) Issue 11 . - No. 43.
ISSN 1432-2021
DOI der Verlagsversion:

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Project information

Project financing: Deutsche Forschungsgemeinschaft


We performed molecular dynamics simulations based on density functional theory to systematically investigate the Fe–Ni–C system including (1) pure Fe and Ni; (2) binary Fe–Ni, Fe–C, and Ni–C; and (3) ternary Fe–Ni–C liquid compositions at 3000 K and three simulation volumes corresponding to pressure (P) up to 83 GPa. Liquid structural properties, including coordination numbers, are analyzed using partial radial distribution functions. Self-diffusion coefficients are determined based on the atomic trajectories and the asymptotic slope of the time-dependent mean-square displacement. The results indicate that the average interatomic distance between two Fe atoms (rFe–Fe) decreases with P and is sensitive to Ni (XNi) and C (XC) concentration, although the effects are opposite: rFe–Fe decreases with increasing XNi, but increases with increasing XC. Average rFe–C and rNi–C values also decrease with increasing XNi and generally remain constant between the two lowest P points, corresponding to a coordination change of carbon from ~ 6.8 to ~ 8.0, and then decrease with additional P once the coordination change is complete. Carbon clustering occurs in both binary (especially Ni–C) and ternary compositions with short-range rC-C values (~ 1.29 to ~ 1.57 Å), typical for rC-C in diamond and graphite. The self-diffusion results are generally consistent with high-P diffusion data extrapolated from experiments conducted at lower temperature (T). A subset of additional simulations was conducted at 1675 and 2350 K to estimate the effect of T on diffusion, yielding an activation enthalpy of ~ 53 kJ/mol and activation volume of ~ 0.5 cm3/mol.

Further data

Item Type: Article in a journal
Keywords: Liquid iron alloys; Nickel; Carbon; High pressure; Compositional effect; Core formation
DDC Subjects: 500 Science > 550 Earth sciences, geology
Institutions of the University: Research Institutions > Central research institutes > Bavarian Research Institute of Experimental Geochemistry and Geophysics - BGI
Research Institutions
Research Institutions > Central research institutes
Language: English
Originates at UBT: Yes
URN: urn:nbn:de:bvb:703-epub-7028-3
Date Deposited: 09 Jun 2023 06:38
Last Modified: 21 Sep 2023 12:38


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