Liquid iron
Pro Research Analysisby 
Searched over 200M research papers for "liquid iron"
Properties and Behavior of Liquid Iron Under Extreme Conditions
Density and Sound Velocity of Liquid Iron
Recent studies have provided significant insights into the properties of liquid iron under extreme conditions. The density of liquid iron has been measured up to 116 GPa and 4350 K using static compression experiments. Additionally, the longitudinal sound velocity was determined up to 45 GPa and 2700 K through inelastic x-ray scattering measurements. These findings, combined with previous shock-wave data, have led to the development of a thermal equation of state for liquid iron. This equation indicates that Earth's outer core has a 7.5%-7.6% density deficit and a 3.7%-4.4% velocity excess compared to liquid iron, while the adiabatic bulk modulus remains almost identical1.
Structural Properties of Liquid Iron
The structure of liquid iron at high pressures has been extensively studied using x-ray scattering in a laser-heated diamond anvil cell. These studies reveal that liquid iron maintains a close-packed hard-sphere structure along the melting curve up to 58 GPa. This structural consistency places important constraints on the thermodynamic and transport properties of liquid iron, as well as the melting curve of iron2. Further molecular-dynamics simulations have confirmed that liquid iron under Earth's core conditions behaves as a close-packed simple liquid with diffusion coefficients and viscosities similar to those of typical simple liquids under ambient conditions3.
Thermodynamic Properties and Equation of State
The equation of state (EoS) and thermodynamic properties of non-magnetic liquid iron have been investigated through ab initio molecular dynamics simulations at pressures ranging from 60 to 420 GPa and temperatures between 4000 and 7000 K. These studies show that pure liquid iron has an 8%-10% larger density and a 3%-10% larger bulk modulus compared to the seismological data of Earth's outer core. The P wave velocity of liquid iron exhibits marginal temperature dependence, similar to the bulk sound velocity of solid iron. These findings provide fundamental data for thermochemical modeling of Earth's core4.
Wetting Behavior and Corrosion Resistance
The wetting behavior of liquid iron on various substrates, including forsterite, mullite, spinel, and quasi-corundum, has been studied through sessile drop experiments. The results indicate that the wetting characteristics are significantly influenced by FeO compounds formed via oxidation of the liquid iron. Forsterite and mullite substrates showed improved wetting due to the formation of ternary phases at the interface, while spinel exhibited enhanced corrosion resistance as it did not form FeO-based compounds. Quasi-corundum demonstrated superior resistance to liquid iron compared to forsterite or mullite5.
Solubility of Light Elements in Liquid Iron
The solubility of oxygen (O) and silicon (Si) in liquid iron in equilibrium with (Mg,Fe)SiO3 perovskite has been investigated using laser-heated diamond anvil cells and analytical transmission electron microscopy. The results show that the dissolution of O and Si into molten iron increases with pressure, with the quenched liquid iron containing 5.3 wt% O and 2.8 wt% Si at 97 GPa and 3150 K. These findings suggest that O and Si are significant light elements in the core, potentially accounting for the core density deficit9.
Conclusion
The research on liquid iron under extreme conditions has provided valuable insights into its density, sound velocity, structural properties, thermodynamic behavior, wetting characteristics, and solubility of light elements. These findings are crucial for understanding the properties of Earth's outer core and for developing accurate thermochemical models. The consistency in structural properties and the influence of light elements like O and Si highlight the complex interactions within the core, contributing to our broader understanding of planetary interiors.
Sources and full results
Most relevant research papers on this topic
Equation of State of Liquid Iron under Extreme Conditions.
Earth's outer core has a density deficit of 7.5%-7.6% and a velocity excess of 3.7%-4.4% compared to liquid iron, with an almost identical adiabatic bulk modulus.
Structure of liquid iron at pressures up to 58 GPa.
Liquid iron at high pressures is a close-packed hard-sphere liquid, preserving its shape along the melting curve, affecting thermodynamic and transport properties.
Highly CitedStructure and dynamics of liquid iron under Earth’s core conditions
Liquid iron in the Earth's core is a close-packed simple liquid with similar diffusion coefficient and viscosity to typical simple liquids under ambient conditions.
Highly CitedThe P‐V‐T equation of state and thermodynamic properties of liquid iron
Liquid iron has a larger density and bulk modulus than the Earth's core, with potential implications for thermochemical modeling of the Earth's core.
Highly CitedA study on the wetting behavior of liquid iron on forsterite, mullite, spinel and quasi-corundum substrates
Liquid iron wetting on forsterite and mullite substrates is improved by FeO compounds, while spinel and quasi-corundum refractories show enhanced resistance to liquid iron compared to forsterite and mullite.
Thermodynamics of Aluminum, Nitrogen and AlN formation in Liquid Iron
Aluminum and nitrogen formation in liquid iron can be accurately predicted using Darken's quadratic formalism.
Dispersive liquid-liquid microextraction coupled with digital image colorimetric analysis for detection of total iron in water and food samples.
Dispersive liquid-liquid microextraction coupled with digital image colorimetric analysis effectively detects total iron in water and food samples without the need for spectral instruments.
Spectrophotometric determination of iron species using a combination of artificial neural networks and dispersive liquid-liquid microextraction based on solidification of floating organic drop.
The developed method effectively separates and speciates iron in water samples, with detection limits of 25 and 8 g L(-1) for iron (II) and (III), respectively, and low standard deviations.
Solubilities of O and Si in liquid iron in equilibrium with (Mg,Fe)SiO3 perovskite and the light elements in the core
Increased pressure in liquid iron increases the dissolution of O and Si, potentially accounting for the 7% core density deficit and depleting the bottom of the mantle in contact with outer core liquid.
Highly CitedDevelopment of new interatomic potentials appropriate for crystalline and liquid iron
New interatomic potentials for crystalline and liquid iron provide more accurate descriptions of atomic interactions at small separations than existing methods.
Highly Cited