DOI: 10.1016/j.epsl.2018.05.002
Scopus记录号: 2-s2.0-85047060454
论文题名: Experimental constraints on the sound velocities of cementite Fe3C to core pressures
作者: Chen B. ; Lai X. ; Li J. ; Liu J. ; Zhao J. ; Bi W. ; Ercan Alp E. ; Hu M.Y. ; Xiao Y.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 494 起始页码: 164
结束页码: 171
语种: 英语
英文关键词: compressional-wave velocity
; inner core
; iron carbide
; magnetic transition
; Poisson's ratio
; shear-wave velocity
Scopus关键词: Acoustic wave velocity
; Carbides
; Emission spectroscopy
; Equations of state
; Oxide superconductors
; Poisson ratio
; Shear flow
; Shear waves
; Wave propagation
; X ray scattering
; Compressional wave velocity
; Inner core
; Iron carbides
; Magnetic transitions
; Shear wave velocity
; Iron compounds
; carbon
; experimental study
; inner core
; iron
; magnetic field
; Poisson ratio
; pressure
; S-wave
; seismic velocity
英文摘要: Sound velocities of cementite Fe3C have been measured up to 1.5 Mbar and at 300 K in a diamond anvil cell using the nuclear resonant inelastic X-ray scattering (NRIXS) technique. From the partial phonon density of states (pDOS) and equation of state (EOS) of Fe3C, we derived its elastic parameters including shear modulus, compressional (VP) and shear-wave (VS) velocities to core pressures. A pressure-induced spin-pairing transition in the powdered Fe3C sample was found to occur gradually between 10 and 50 GPa by the X-ray Emission Spectroscopy (XES) measurements. Following the completion of the spin-pairing transition, the VP and VS of low-spin Fe3C increased with pressure at a markedly lower rate than its high-spin counterpart. Our results suggest that the incorporation of carbon in solid iron to form iron carbide phases, Fe3C and Fe7C3, could effectively lower the VS but respectively raise the Poisson's ratio by 0.05 and 0.07 to approach the seismically observed values for the Earth's inner core. The comparison with the preliminary reference Earth model (PREM) implies that an inner core composition containing iron and its carbon-rich alloys can satisfactorily explain the observed seismic properties of the inner core. © 2018 Elsevier B.V.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109856
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI, United States; Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI, United States; Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, United States; Advanced Photon Source, Argonne National Laboratory, Argonne, IL, United States; HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, United States
Recommended Citation:
Chen B.,Lai X.,Li J.,et al. Experimental constraints on the sound velocities of cementite Fe3C to core pressures[J]. Earth and Planetary Science Letters,2018-01-01,494