The Fe-O (Iron-Oxygen) System

Wriedt, H. A.

doi:10.1007/bf02645713

Cited by 100 publications

(55 citation statements)

References 221 publications

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“…The stoichiometry of the phase here described falls within the most puzzling region of the Fe-O phase diagram, between wüstite and magnetite (7,(16)(17)(18)(19). With increasing temperature, at ambient pressure, the Fe-O phase diagram at 44 at.…”

Section: Energetics and Stability Ofmentioning

confidence: 65%

Discovery of the recoverable high-pressure iron oxide Fe₄O₅

Lavina

Dera

Kim

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

130

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Phases of the iron–oxygen binary system are significant to most scientific disciplines, directly affecting planetary evolution, life, and technology. Iron oxides have unique electronic properties and strongly interact with the environment, particularly through redox reactions. The iron–oxygen phase diagram therefore has been among the most thoroughly investigated, yet it still holds striking findings. Here, we report the discovery of an iron oxide with formula Fe 4 O 5 , synthesized at high pressure and temperature. The previously undescribed phase, stable from 5 to at least 30 GPa, is recoverable to ambient conditions. First-principles calculations confirm that the iron oxide here described is energetically more stable than FeO + Fe 3 O 4 at pressure greater than 10 GPa. The calculated lattice constants, equation of states, and atomic coordinates are in excellent agreement with experimental data, confirming the synthesis of Fe 4 O 5 . Given the conditions of stability and its composition, Fe 4 O 5 is a plausible accessory mineral of the Earth’s upper mantle. The phase has strong ferrimagnetic character comparable to magnetite. The ability to synthesize the material at accessible conditions and recover it at ambient conditions, along with its physical properties, suggests a potential interest in Fe 4 O 5 for technological applications.

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Section: Energetics and Stability Ofmentioning

confidence: 65%

Discovery of the recoverable high-pressure iron oxide Fe₄O₅

Lavina

Dera

Kim

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

130

View full text Add to dashboard Cite

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“…11. Integral values obtained from the whole duration of electrolysis trials (A) and (B) give a mean #O 2 of 76% according to Reaction (12). In these electrolysis experiments, #O 2 is decreasing with time to values as low as nearly 60%.…”

Section: Anodic Electrochemical Half Reactionmentioning

confidence: 98%

“…The first imperative condition of MIDEIO is to operate above liquidus temperature of iron metal, which is 1811 K [11,12]. In the following, the selected operating temperature is 1823 K. The source of iron oxide for this process is supposed to come from naturally occurring iron ores.…”

Section: Formulation Of An Electrolyte Composition To Carry Out Mideiomentioning

confidence: 99%

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Electrolysis of iron in a molten oxide electrolyte

Wiencke

Lavelaine

Panteix³

et al. 2018

J Appl Electrochem

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Direct iron production at molten metal state from iron oxides by the sole application of electrical energy represents a possible route to decarbonize steel industry. Although chemically simple, this reaction is difficult to implement due to the problem of the multiple valence states of iron and to an operating temperature above 1811 K. Thermal, chemical, and electrical conditions have been identified based on thermodynamic considerations to carry out this reaction in a laboratory device. Experiments were undertaken to determine the contribution of the thermal level to the decomposition of iron oxide and to estimate the electronic current resulting from iron multiple valence states. The production of liquid iron was obtained resulting in recoverable samples produced at liquid state and from a faradaic process checked in real time by its accompanying anodic oxygen evolution. Graphical AbstractKeywords Molten oxide electrolysis · Metal extraction · Oxide melts · Electrochemical engineering · High-temperature processing

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“…By contrast, the tertiary oxide scale at room temperature comprises mainly Fe 3 O 4 and α-Fe 2 O 3 because the unstable FeO will decompose into Fe 3 O 4 and ferrite (α-Fe) below the eutectoid temperature of FeO at 570 °C [7,8]. Nevertheless, the distributions of these oxide phases depend largely on the heat treatment and atmospheric conditions during hot rolling, and the alloying elements in the steel composition [2,9].…”

Section: Introductionmentioning

confidence: 99%

Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD

Jiang

Zhao

et al. 2015

Surface and Coatings Technology

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Q. (2015). Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD. Surface and Coatings Technology, Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD AbstractThis work presents a fine microstructure and local misorientation study of various oxide phases in the tertiary oxide scale formed on a hot-rolled steel strip via electron back-scattering diffraction (EBSD). Local strain in individual grains of four phases, ferrite (α-Fe), wustite (FeO), magnetite (Fe 3 O 4 ) and hematite (α-Fe 2 O 3 ), has been systematically analysed. The results reveal that Fe 3 O 4 has a lower local strain than α-Fe 2 O 3 , in particular, on the surface and inner layers of the oxide scale. The multiphase oxides along the cracking or α-Fe 2 O 3 penetration generally develop a high local misorientation. Localised stain along the cracks demonstrates that the misorientation tends to be strong near grain boundaries. The high fraction of small Fe 3 O 4 grains accumulate at the oxide-substrate interface, which leads to a dramatic increase in the intensity of local stain. This variation is due mainly to the phase transformation among the oxide phases, i.e., the Fe 3 O 4 particles during their nucleation and growth. The combined action of stress relief and re-oxidisation is proposed to explain the formation of Fe 3 O 4 seam at the oxide-steel interface. The present study offers an intriguing insight into the deformation behaviour of the tertiary oxide scale formed on steels, and may help with understanding the stress-aided oxidation effect of metal alloys. offers an intriguing insight into the deformation behaviour of the tertiary oxide scale formed on steels, and may help with understanding the stress-aided oxidation effect of metal alloys.

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The Fe-O (Iron-Oxygen) System

Cited by 100 publications

References 221 publications

Discovery of the recoverable high-pressure iron oxide Fe₄O₅

Discovery of the recoverable high-pressure iron oxide Fe₄O₅

Electrolysis of iron in a molten oxide electrolyte

Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD

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The Fe-O (Iron-Oxygen) System

Cited by 100 publications

References 221 publications

Discovery of the recoverable high-pressure iron oxide Fe4O5

Discovery of the recoverable high-pressure iron oxide Fe4O5

Electrolysis of iron in a molten oxide electrolyte

Local strain analysis of the tertiary oxide scale formed on a hot-rolled steel strip via EBSD

Contact Info

Product

Resources

About

Discovery of the recoverable high-pressure iron oxide Fe₄O₅

Discovery of the recoverable high-pressure iron oxide Fe₄O₅