High-pressure / High-temperature Behavior of the Methane-Ammonia- Water System up to 3 GPa

2006 ◽  
Vol 61 (12) ◽  
pp. 1573-1576 ◽  
Author(s):  
Alexander Kurnosov ◽  
Leonid Dubrovinsky ◽  
Alexei Kuznetsov ◽  
Vladimir Dmitriev
Keyword(s):  
High Pressure ◽  
Melting Temperature ◽  
Water System ◽  
Hydrate Formation ◽  
Clathrate Hydrates ◽  
Ammonia Water ◽  
High Pressure High Temperature ◽  
In Situ Experiments ◽  
Diamond Anvil ◽  
Methane Clathrate

Melting phase relations in the methane-ammonia-water system up to 3 GPa have been obtained in a series of in situ experiments in externally heated diamond anvil cells. The melting temperature of methane clathrate hydrates increases rapidly above pressures of ~ 1.5 GPa, and does not appear to be significantly affected by the presence of ammonia. The reaction of the hydrate formation at pressures 2 - 3 GPa is kinetically impeded. Our data show that the high-pressure methane hydrate has the maximum melting temperature among the clathrate hydrates studied so far.

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

scholarly journals High-Pressure Synthesis and Study of NO+NO3− and NO2+NO3− Ionic Solids

2009 ◽  
Vol 2009 ◽  
pp. 1-11 ◽  
Author(s):  
A. Yu. Kuznetsov ◽  
L. Dubrovinsky ◽  
A. Kurnosov ◽  
M. M. Lucchese ◽  
W. Crichton ◽  
...  
Keyword(s):  
High Pressure ◽  
Ionic Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dinitrogen Pentoxide ◽  
High Pressure High Temperature ◽  
Ionic Solids ◽  
Ionic Compounds ◽  
Diamond Anvil ◽  
Pressure Synthesis

Nitrosonium-nitrate NO+NO3− and dinitrogen pentoxide NO2+NO3− ionic crystals were synthesized by laser heating of a condensed oxygen-rich O2-N2 mixture compressed to different pressures, up to 40 GPa, in a diamond anvil cell (DAC). High-pressure/high-temperature Raman and X-ray diffraction studies of synthesized samples disclosed a transformation of NO+NO3− compound to NO2+NO3− crystal at temperatures above ambient and pressures below 9 GPa. High-pressure experiments revealed previously unreported bands in Raman spectra of NO+NO3− and NO2+NO3− ionic crystals. Structural properties of both ionic compounds are analyzed. Obtained experimental results support a hypothesis of a rotational disorder of NO+ complexes in NO+NO3− and indicate a rotational disorder of ionic complexes in NO2+NO3− solid.

scholarly journals Gas hydrates at high pressure

2014 ◽  
Vol 70 (a1) ◽  
pp. C900-C900
Author(s):  
J. Loveday ◽  
C. Bull ◽  
A. Frantzana ◽  
C. Wilson ◽  
D. Amos ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Gas Hydrates ◽  
Water System ◽  
X Ray Diffraction ◽  
Ammonia Water ◽  
Fundamental Insight ◽  
Gas Interactions ◽  
Water Gas ◽  
And Storage

The behaviour of gas hydrates at high pressure is of wide interest and importance. Gas hydrates are stablised by water-gas repulsive interactions. Information on the effect of changing density on these water-gas interactions provides fundamental insight into the nature of the water potential. Gas hydrates are also widely found in nature and systems like the ammonia-water and methane-water systems form the basis of 'mineralogy' of planetary bodies like Saturn's moon Titan. Finally, gas hydrates offer the possibility of cheap environmentally inert transportation and storage for gases like carbon dioxide and hydrogen. We have been carrying out investigations of a range of gas hydrates at high pressure using neutron and x-ray diffraction as well as other techniques. Results from these studies including; the phase diagram of the ammonia water system, the occupancies of hexgonal clathrate structures, and new structures in the carbon dioxide water system, will be presented.

scholarly journals Carbide Formation in Refractory Mo15Nb20Re15Ta30W20 Alloy under a Combined High-Pressure and High-Temperature Condition

Entropy ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 718
Author(s):  
Congyan Zhang ◽  
Uttam Bhandari ◽  
Congyuan Zeng ◽  
Huan Ding ◽  
Shengmin Guo ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Mechanical Performance ◽  
Ambient Pressure ◽  
High Entropy Alloy ◽  
Carbide Formation ◽  
High Entropy ◽  
Temperature Conditions ◽  
High Pressure High Temperature ◽  
Diamond Anvil

In this work, the formation of carbide with the concertation of carbon at 0.1 at.% in refractory high-entropy alloy (RHEA) Mo15Nb20Re15Ta30W20 was studied under both ambient and high-pressure high-temperature conditions. The x-ray diffraction of dilute carbon (C)-doped RHEA under ambient pressure showed that the phases and lattice constant of RHEA were not influenced by the addition of 0.1 at.% C. In contrast, C-doped RHEA showed unexpected phase formation and transformation under combined high-pressure and high-temperature conditions by resistively employing the heated diamond anvil cell (DAC) technique. The new FCC_L12 phase appeared at 6 GPa and 809 °C and preserved the ambient temperature and pressure. High-pressure and high-temperature promoted the formation of carbides Ta3C and Nb3C, which are stable and may further improve the mechanical performance of the dilute C-doped alloy Mo15Nb20Re15Ta30W20.

Phase Diagram and High-Pressure Boundary of Hydrate Formation in the Ethane−Water System

2006 ◽  
Vol 110 (43) ◽  
pp. 21788-21792 ◽  
Author(s):  
Alexander V. Kurnosov ◽  
Andrey G. Ogienko ◽  
Sergei V. Goryainov ◽  
Eduard G. Larionov ◽  
Andrey Y. Manakov ◽  
...  
Keyword(s):  
Phase Diagram ◽  
High Pressure ◽  
Water System ◽  
Hydrate Formation

Phase Diagram and High-Pressure Boundary of Hydrate Formation in the Carbon Dioxide−Water System

2009 ◽  
Vol 113 (20) ◽  
pp. 7257-7262 ◽  
Author(s):  
Andrej Yu. Manakov ◽  
Yuriy A. Dyadin ◽  
Andrey G. Ogienko ◽  
Alexander V. Kurnosov ◽  
Eugeny Ya. Aladko ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Phase Diagram ◽  
High Pressure ◽  
Water System ◽  
Hydrate Formation

scholarly journals Oxidation of High Yield Strength Metals Tungsten and Rhenium in High-Pressure High-Temperature Experiments of Carbon Dioxide and Carbonates

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 676 ◽  
Author(s):  
Raquel Chuliá-Jordán ◽  
David Santamaría-Pérez ◽  
Tomás Marqueño ◽  
Javier Ruiz-Fuertes ◽  
Dominik Daisenberger
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Yield Strength ◽  
High Pressures ◽  
Chemical Reactivity ◽  
High Yield ◽  
Reaction Products ◽  
High Yield Strength ◽  
High Pressure High Temperature ◽  
Diamond Anvil

The laser-heating diamond-anvil cell technique enables direct investigations of materials under high pressures and temperatures, usually confining the samples with high yield strength W and Re gaskets. This work presents experimental data that evidences the chemical reactivity between these refractory metals and CO2 or carbonates at temperatures above 1300 °Ϲ and pressures above 6 GPa. Metal oxides and diamond are identified as reaction products. Recommendations to minimize non-desired chemical reactions in high-pressure high-temperature experiments are given.

High-pressure boundary of hydrate formation in the tetrahydrofuran–water system

2000 ◽  
Vol 10 (2) ◽  
pp. 80-81 ◽  
Author(s):  
Andrei Yu. Manakov ◽  
Sergei V. Goryainov ◽  
Anna Yu. Likhacheva ◽  
Boris A. Fursenko ◽  
Yuri A. Dyadin ◽  
...  
Keyword(s):  
High Pressure ◽  
Water System ◽  
Hydrate Formation
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