Metastability in the H2O and D2O Systems at High Pressure

1983 ◽  
Vol 22 ◽  
Author(s):  
G. J. Piermarini ◽  
R. G. Munro ◽  
S. Block
Keyword(s):  
High Pressure ◽  
Triple Point ◽  
Pressure Range ◽  
Diamond Anvil Cell ◽  
Coexistence Curve ◽  
Equilibrium Thermodynamic ◽  
Polarizing Microscopy ◽  
Metastable Extension ◽  
Diamond Anvil ◽  
Optical Polarizing Microscopy

ABSTRACTThe pressure and temperature parameters which delineate the equilibrium thermodynamic stability fields of the liquid, VI and VII phases, includinq the triple point, were measured for the H2;0 and D2;0 systems over the pressure range, 0.8 to 2.4 GPa, and the temperature interval, 20 to 135 °C. The phenomenon of metastability associated with the liquid-VII phase boundary was observed during this work; and, subsequently, a metastable extension of this coexistence curve was determined from the liquid-VI-VII triple point down to 20 °C for both H2;0 and D2;0. The measurements were made by optical polarizing microscopy in conjunction with a diamond anvil cell equipped with a miniature resistance coil heatinq element. Pressures were measured by the ruby fluorescence method.

scholarly journals Wardite (NaAl3(PO4)2(OH)4·2H2O) at High Pressure: Compressional Behavior and Structure Evolution

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 877
Author(s):  
G. Diego Gatta ◽  
Davide Comboni ◽  
Paolo Lotti ◽  
Alessandro Guastoni ◽  
Nicola Rotiroti ◽  
...  
Keyword(s):  
High Pressure ◽  
Pressure Range ◽  
Diamond Anvil Cell ◽  
Atomic Scale ◽  
Deformation Mechanisms ◽  
Structure Evolution ◽  
Synchrotron Diffraction ◽  
Diamond Anvil ◽  
Murnaghan Equation

The high-pressure behavior of wardite, NaAl3(PO4)2(OH)4·2H2O (a = 7.0673(2) Å, c = 19.193(9) Å, Sp. Gr. P41212), has been investigated by in-situ single-crystal synchrotron diffraction experiments up to 9 GPa, using a diamond anvil cell under quasi-hydrostatic conditions. This phosphate does not experience any pressure-induced phase transition, or anomalous compressional behavior, within the pressure-range investigated: its compressional behavior is fully elastic and all the deformation mechanisms, at the atomic scale, are reversible upon decompression. A second-order Birch–Murnaghan Equation of State was fitted to the experimental data, weighted by their uncertainty in pressure (P) and volume (V), with the following refined parameters: V0 = 957.8(2) Å3 and KV0 = −V0(∂P/∂V)P0,T0 = 85.8(4) GPa (βV0 = 1/KV0 = 0.01166(5) GPa−1). Axial bulk moduli were also calculated, with: K0(a) = 98(3) GPa (β0(a) = 0.0034(1) GPa−1) and K0(c) = 64(1) GPa (β0(c) = 0.0052(1) GPa−1). The anisotropic compressional scheme is: K0(a):K0(c) = 1.53:1. A series of structure refinements were performed on the basis of the intensity data collected in compression and decompression. The mechanisms at the atomic scale, responsible for the structure anisotropy of wardite, are discussed.

scholarly journals The Bridgmanite–Akimotoite–Majorite Triple Point Determined in Large Volume Press and Laser-Heated Diamond Anvil Cell

Minerals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 67
Author(s):  
Britany L. Kulka ◽  
Jonathan D. Dolinschi ◽  
Kurt D. Leinenweber ◽  
Vitali B. Prakapenka ◽  
Sang-Heon Shim
Keyword(s):  
High Pressure ◽  
Triple Point ◽  
Large Volume ◽  
Diamond Anvil Cell ◽  
Experimental Methods ◽  
Diamond Anvil ◽  
Laser Heated ◽  
Good Agreement

The bridgmanite–akimotoite–majorite (Bm–Ak–Mj or BAM) triple point in MgSiO3 has been measured in large-volume press (LVP; COMPRES 8/3 assembly) and laser-heated diamond anvil cell (LHDAC). For the LVP data, we calculated pressures from the calibration provided for the assembly. For the LHDAC data, we conducted in situ determination of pressure at high temperature using the Pt scale at synchrotron. The measured temperatures of the triple point are in good agreement between LVP and LHDAC at 1990–2000 K. However, the pressure for the triple point determined from the LVP is 3.9 ± 0.6 GPa lower than that from the LHDAC dataset. The BAM triple point determined through these experiments will provide an important reference point in the pressure–temperature space for future high-pressure experiments and will allow mineral physicists to compare the pressure–temperature conditions measured in these two different experimental methods.

scholarly journals The Akimotoite--Majorite--Bridgmanite Triple Point Determined in Large Volume Press and Laser-Heated Diamond Anvil Cell

2019 ◽  
Author(s):  
Britany Kulka ◽  
Jonathan Dolinschi ◽  
Kurt Leinenweber ◽  
Vitali Prakapenka ◽  
Sang-Heon Shim
Keyword(s):  
High Pressure ◽  
Triple Point ◽  
Large Volume ◽  
Diamond Anvil Cell ◽  
Experimental Methods ◽  
Diamond Anvil ◽  
Laser Heated ◽  
Good Agreement

The akimotoite--majorite--bridgmanite (Ak--Mj--Bm) triple point in MgSiO3 has been measured in large-volume press (LVP; COMPRES 8/3 assembly) and laser-heated diamond anvil cell (LHDAC). For the LVP data, we calculated pressures from the calibration by Leinenweber (2012). For the LHDAC data, we conducted \textit{in situ} determination of pressure at high temperature using the Pt scale by Dorogokupets and Dewaele (2007) at synchrotron. The measured temperatures of the triple point are in good agreement between LVP and LHDAC at 1990-2000 K. However, the pressure for the triple point determined from the LVP is 3.9+/-0.6~GPa lower than that from the LHDAC dataset. The triple point determined through these experiments will provide an important reference point in the pressure-temperature space for future high-pressure experiments and allow mineral physicists to compare the pressure--temperature conditions measured in these two different experimental methods.

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.

PHASE TRANSITION IN LAYERED PEROVSKITE LIKE MANGANATE Ca3Mn2O7 UNDER HIGH PRESSURE

2001 ◽  
Vol 15 (18) ◽  
pp. 2491-2497 ◽  
Author(s):  
J. L. ZHU ◽  
L. C. CHEN ◽  
R. C. YU ◽  
F. Y. LI ◽  
J. LIU ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
The Other ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Diamond Anvil

In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca 3 Mn 2 O 7 under pressures up to 35 GPa have been performed by using diamond anvil cell with synchrotron radiation. The results show that the structure of layered perovskite-like manganate Ca 3 Mn 2 O 7 is unstable under pressure due to the easy compression of NaCl-type blocks. The structure of Ca 3 Mn 2 O 7 underwent two phase transitions under pressures in the range of 0~35 GPa. One was at about 1.3 GPa with the crystal structure changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic back to another tetragonal.

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