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iron carbides

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Journal Article
Published: 01 December 2020
Russ. Geol. Geophys. (2020) 61 (12): 1345–1353.
...N.E. Sagatov; P.N. Gavryushkin; I.V. Medrish; T.M. Inerbaev; K.D. Litasov Abstract —Based on first-principle calculations in the framework of the density functional theory and structure prediction algorithms, we have determined iron carbide phases stable at the Earth’s core pressures...
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Journal Article
Published: 01 January 2015
Russ. Geol. Geophys. (2015) 56 (1-2): 164–171.
... at the core pressures. Therefore, a theoretical modeling of iron carbides at ≤ 500 GPa is carried out. Energetically stable phases and the pressures of magnetic transitions at 0 K are determined. The parameters of magnetic transitions for Fe 7 C 3 and Fe 3 C are consistent with those determined...
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Journal Article
Published: 01 January 2019
American Mineralogist (2019) 104 (1): 1.
... primitive C1 chondrites, which are believed to be the building blocks of our planet, contain 3.5 wt% C. The Fe-C system has been proposed as a candidate component in the Earth's core, largely based on its high cosmochemical abundance, the frequent occurrence of iron carbide phases (e.g., Fe 3 C...
Image
Densities of iron, iron carbides, and Earth’s core as a function of pressure. Data sources: PREM (Dziewonski and Anderson 1981). Dashed line: Shocked Fe along a Hugoniot (Brown 2001). Solid line: statically compressed hcp Fe at 300 K (Mao et al. 1990). Note slightly higher densities in a more recent paper (Dewaele et al. 2006). Dotted line: Statically compressed hcp Fe at 5000 K (Dubrovinsky et al. 2000; Komabayashi and Fei 2010). Solid Fe3C at 300 K (Ono and Mibe 2010; Sata et al. 2010; Scott et al. 2001) (vertical bars, solid circles and open circles respectively). Liquid Fe3C (Terasaki et al. 2010). Solid Fe7C3 at 300 K (squares) and high temperature (triangles) (Nakajima et al. 2011).
Published: 01 January 2013
Figure 5 Densities of iron, iron carbides, and Earth’s core as a function of pressure. Data sources: PREM ( Dziewonski and Anderson 1981 ). Dashed line: Shocked Fe along a Hugoniot ( Brown 2001 ). Solid line: statically compressed hcp Fe at 300 K ( Mao et al. 1990 ). Note slightly higher
Journal Article
Published: 01 April 2011
The Canadian Mineralogist (2011) 49 (2): 555–572.
...Felix V. Kaminsky; Richard Wirth Abstract Iron carbides in association with native iron, graphite, and magnetite were identified in a crystal of diamond from the Juina area, Brazil, that contains a series of other, deep-mantle mineral inclusions. Among the iron carbides, Fe 3 C, Fe 2 C (“chalypite...
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Compositional ternary plot of natural iron carbides and nitrides from different localities (in atom%). See references in note to Table 3. (Color online.)
Published: 01 August 2017
Figure 6. Compositional ternary plot of natural iron carbides and nitrides from different localities (in atom%). See references in note to Table 3 . (Color online.)
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Enthalpy of formation per atom for the studied iron carbides, Fe, and diamond depending on pressure.
Published: 01 January 2015
Fig. 1. Enthalpy of formation per atom for the studied iron carbides, Fe, and diamond depending on pressure.
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The magnetic moment (μB) of iron carbides vs. pressure.
Published: 01 January 2015
Fig. 5. The magnetic moment (μB) of iron carbides vs. pressure.
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Calculated density of the NM phases of iron carbides at the core parameters. Data for carbides are shown at 5000 K (see the text). Blue lines show data for iron, after (Seagle et al., 2006); red dashed line, the profile of density, according to the PREM (Dziewonski and Anderson, 1981); and vertical lines show uncertainty for the PREM.
Published: 01 January 2015
Fig. 7. Calculated density of the NM phases of iron carbides at the core parameters. Data for carbides are shown at 5000 K (see the text). Blue lines show data for iron, after ( Seagle et al., 2006 ); red dashed line, the profile of density, according to the PREM ( Dziewonski and Anderson, 1981
Journal Article
Published: 01 March 2019
American Mineralogist (2019) 104 (3): 325–332.
...Feng Zhu; Jie Li; David Walker; Jiachao Liu; Xiaojing Lai; Dongzhou Zhang Abstract The Eckstrom-Adcock iron carbide, nominally Fe 7 C 3 , is a potential host of reduced carbon in Earth's mantle and a candidate component of the inner core. Non-stoichiometry in Fe 7 C 3 has been observed previously...
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Journal Article
Published: 01 January 2016
Russ. Geol. Geophys. (2016) 57 (1): 176–189.
...Yu.V. Bataleva; Yu.N. Palyanov; Yu.M. Borzdov; O.A. Bayukov; N.V. Sobolev Abstract To estimate conditions for the stability of iron carbide under oxidation conditions and to assess the possibility of formation of elemental carbon by interaction between iron carbide and oxides, experimental modeling...
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Journal Article
Published: 01 September 2019
American Mineralogist (2019) 104 (9): 1351–1355.
...Chi Ma; Alan E. Rubin Abstract Edscottite (IMA 2018-086a), Fe 5 C 2 , is a new iron carbide mineral that occurs with low-Ni iron (kamacite), taenite, nickelphosphide (Ni-dominant schreibersite), and minor cohenite in the Wedder-burn iron meteorite, a Ni-rich member of the group IAB complex...
FIGURES
Journal Article
Published: 01 July 2011
American Mineralogist (2011) 96 (7): 1158–1165.
... calculations, Wood (1993) suggested that an iron-carbide Fe 3 C might be a constituent of the Earth’s inner core that solidified from the carbon-rich liquid outer core. However, recent high-pressure experiments on the Fe-C system have shown that Fe 7 C 3 rather than Fe 3 C might be stabilized under core...
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HAADF image of a graphite – iron carbide inclusion in diamond (foil #2049). Iron carbide is developed along the interface with diamond and as finely dispersed bright spots in the graphite matrix.
Published: 01 April 2011
F ig . 5. HAADF image of a graphite – iron carbide inclusion in diamond (foil #2049). Iron carbide is developed along the interface with diamond and as finely dispersed bright spots in the graphite matrix.
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Iron carbide lamellae in foil no. 4588. (a) HAADF image of two iron carbide lamellae within the iron carbonitride grain included within diamond. The areas over which EDX analyses were determined are shown in red squares (1 = a brighter contrasted volume within the lamella; 2 = the gray matrix of the lamella). The bright lines in the hosting carbonitride are dislocation lines. (b) EEL spectrum of the matrix of the thick lamella. The calculated ratio of Fe/C from this spectrum is 2.46, which is close to the ideal value of 2.33 for Fe7C3. (c and d) EDX spectra of iron carbide, Fe7C3 (c) from matrix without admixture of Si; (d) from bright area no. 1 with a noticeable admixture of Si. (Color online.)
Published: 01 August 2017
Figure 4. Iron carbide lamellae in foil no. 4588. ( a ) HAADF image of two iron carbide lamellae within the iron carbonitride grain included within diamond. The areas over which EDX analyses were determined are shown in red squares (1 = a brighter contrasted volume within the lamella; 2
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The structure of the iron carbide cohenite [(Fe,Ni,Co)3C] (orthorhombic, space group Pbnm; a = 4.518 Å, b = 5.069 Å; c = 6.736 Å; Z = 4). Carbon and iron atoms appear in blue and gold, respectively. [Animation 4: For readers of the electronic version, click the image for an animation of the iron carbide cohenite crystal structure.]
Published: 01 January 2013
Figure 6 The structure of the iron carbide cohenite [(Fe,Ni,Co) 3 C] (orthorhombic, space group Pbnm; a = 4.518 Å, b = 5.069 Å; c = 6.736 Å; Z = 4). Carbon and iron atoms appear in blue and gold, respectively. [ Animation 4 : For readers of the electronic version, click the image
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TEM bright-field image of iron carbide platelets in a plate-like inclusion in diamond (foil #2063). The strong dark diffraction contrast of the iron carbide platelets is due to the similar orientation of the individual platelets, oriented with a low-index zone axis parallel to the optical axis.
Published: 01 April 2011
F ig . 8. TEM bright-field image of iron carbide platelets in a plate-like inclusion in diamond (foil #2063). The strong dark diffraction contrast of the iron carbide platelets is due to the similar orientation of the individual platelets, oriented with a low-index zone axis parallel
Journal Article
Published: 01 January 2015
Russ. Geol. Geophys. (2015) 56 (1-2): 143–154.
... in the crystallization of iron carbide in assemblage with magnesiowustite (Fe# = 0.75–0.85). It is shown that the reduction of carbonate or CO 2 fluid by iron carbide and parallel redox interaction of magnesiowustite with CO 2 produce graphite in assemblage with Fe 3+ -containing magnesiowüstite. In the temperature...
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TEM images of a plate-like inclusion in diamond, composed of iron carbide in a graphite matrix (foil #2053). A) Bright field (BF) image. The dark rounded shadow is due to the perforated carbon film onto which the TEM foil rests. B) Dark field (DF) image. The bright areas represent iron carbide crystals with the same crystallographic orientation.
Published: 01 April 2011
F ig . 6. TEM images of a plate-like inclusion in diamond, composed of iron carbide in a graphite matrix (foil #2053). A) Bright field (BF) image. The dark rounded shadow is due to the perforated carbon film onto which the TEM foil rests. B) Dark field (DF) image. The bright areas represent iron
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High-resolution TEM image of the top of an iron carbide platelet tip in foil #2063. The tip is coated with a thin (ca. 5–6 nm) layer of graphite. Lattice fringes of (0002) graphite displayed in the image have a spacing of 0.335 nm. The assemblage of iron carbide with the well-crystallized layer of graphite is embedded in poorly crystallized graphite or amorphous carbon.
Published: 01 April 2011
F ig . 9. High-resolution TEM image of the top of an iron carbide platelet tip in foil #2063. The tip is coated with a thin ( ca . 5–6 nm) layer of graphite. Lattice fringes of (0002) graphite displayed in the image have a spacing of 0.335 nm. The assemblage of iron carbide with the well