High-pressure and high-temperature reactions between silicates and liquid iron alloys, in the diamond anvil cell, studied by analytical electron microscopy

1992 ◽  
Vol 97 (B4) ◽  
pp. 4477 ◽  
Author(s):  
Francoise Goarant ◽  
Francois Guyot ◽  
Jean Peyronneau ◽  
Jean-Paul Poirier
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
High Temperature ◽  
Liquid Iron ◽  
Diamond Anvil Cell ◽  
Analytical Electron Microscopy ◽  
Iron Alloys ◽  
Analytical Electron ◽  
Diamond Anvil ◽  
High Temperature Reactions

scholarly journals The thermal conductivity of the Earth's core and implications for its thermal and compositional evolution

2020 ◽  
Author(s):  
Kenji Ohta ◽  
Kei Hirose
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Thermal History ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
Iron Alloys ◽  
Compositional Evolution ◽  
The Earth ◽  
Diamond Anvil ◽  
High Pressures And Temperatures

Abstract Precise determinations of the thermal conductivity of iron alloys at high pressures and temperatures are essential for understanding the thermal history and dynamics of the metallic cores of the Earth. We review relevant high-pressure experiments using a diamond-anvil cell and discuss implications of high core conductivity for its thermal and compositional evolution.

scholarly journals The Phase Transition and Dehydration in Epsomite under High Temperature and High Pressure

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 75 ◽  
Author(s):  
Linfei Yang ◽  
Lidong Dai ◽  
Heping Li ◽  
Haiying Hu ◽  
Meiling Hong ◽  
...  
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
High Pressure ◽  
High Temperature ◽  
Magnesium Sulfate ◽  
Room Temperature ◽  
Diamond Anvil Cell ◽  
Vibrational Modes ◽  
Diamond Anvil ◽  
T Phase

The phase stability of epsomite under a high temperature and high pressure were explored through Raman spectroscopy and electrical conductivity measurements in a diamond anvil cell up to ~623 K and ~12.8 GPa. Our results verified that the epsomite underwent a pressure-induced phase transition at ~5.1 GPa and room temperature, which was well characterized by the change in the pressure dependence of Raman vibrational modes and electrical conductivity. The dehydration process of the epsomite under high pressure was monitored by the variation in the sulfate tetrahedra and hydroxyl modes. At a representative pressure point of ~1.3 GPa, it was found the epsomite (MgSO4·7H2O) started to dehydrate at ~343 K, by forming hexahydrite (MgSO4·6H2O), and then further transformed into magnesium sulfate trihydrate (MgSO4·3H2O) and anhydrous magnesium sulfate (MgSO4) at higher temperatures of 373 and 473 K, respectively. Furthermore, the established P-T phase diagram revealed a positive relationship between the dehydration temperature and the pressure for epsomite.

Metal Colloids in Oxides*

1983 ◽  
Vol 24 ◽  
Author(s):  
J. Narayan ◽  
Y. Chen ◽  
R. M. Moon
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Optical Absorption ◽  
Analytical Electron Microscopy ◽  
Optical Absorption Spectra ◽  
Temperature Reduction ◽  
Nucleation Sites ◽  
Analytical Electron ◽  
Bcc Structure ◽  
Fcc Structure

ABSTRACTA method, based upon subtractive coloration or high-temperature reduction, was developed to produce metal precipitates or colloids in oxides. The structure, symmetry, morphology and composition of precipitates were analyzed by analytical electron microscopy and neutron scattering technioues. In the MgO:Ni system, the colloids were coherent nickel precipitates having a fcc structure (a0 = 3.52 Å), and occasionally a bcc structure (a0 = 2.88 Å). The coherent precipitates were analyzed to have either <100>m,∣∣ <111>p or <l00>m ∣∣<100>p matrix-precipitate orientation relationship depending upon the high-temperature reduction treatment. The optical absorption spectra of these materials were characterized by broad optical bands centered near 2.2 and 5.0 eV. By changing the size distribution of the precipitates, it was possible to obtain optical spectra of these materials suited for solar selective absorber applications. The dislocations and sub-boundaries provided nucleation sites for the formation of precipitates, and decreased the temperature of reduction. By providing sources of dislocations, the precipitates enhance the ductility and inhibit the propagation of cracks.

scholarly journals Experimental method for in situ determination of material textures at simultaneous high pressure and high temperature by means of radial diffraction in the diamond anvil cell

2009 ◽  
Vol 80 (10) ◽  
pp. 104501 ◽  
Author(s):  
Hanns-Peter Liermann ◽  
Sébastien Merkel ◽  
Lowell Miyagi ◽  
Hans-Rudolf Wenk ◽  
Guoyin Shen ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Experimental Method ◽  
Diamond Anvil Cell ◽  
Diamond Anvil

Cryogenic gas loading in a Mao–Bell-type diamond anvil cell for high pressure-high temperature investigations

2008 ◽  
Vol 79 (7) ◽  
pp. 076103 ◽  
Author(s):  
M. Sekar ◽  
N. R. Sanjay Kumar ◽  
P. Ch. Sahu ◽  
N. V. Chandra Shekar ◽  
N. Subramanian
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Diamond Anvil Cell ◽  
High Pressure High Temperature ◽  
Diamond Anvil
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