Effects of fluid and melt density and structure on high-pressure and high-temperature experimental studies of hydrogen isotope partitioning between coexisting melt and aqueous fluid

2013 ◽  
Vol 98 (10) ◽  
pp. 1754-1764 ◽  
Author(s):  
B. Mysen
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Hydrogen Isotope ◽  
Experimental Studies ◽  
Aqueous Fluid ◽  
Melt Density ◽  
Isotope Partitioning

Synthesis and characterization of NaAlSi2O6 jadeite doped with different metallic oxides under high pressure and high temperature

2019 ◽  
Vol 33 (34) ◽  
pp. 1950427
Author(s):  
Liang Zhao ◽  
Hongan Ma ◽  
Chao Fang ◽  
Luyao Ding ◽  
Baomin Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
High Temperature ◽  
Raw Materials ◽  
Experimental Studies ◽  
Molar Ratio ◽  
Molecular Vibration ◽  
Fine Grained ◽  
Composition Formula ◽  
Geological Conditions

According to the mineral composition [Formula: see text] of jadeite, [Formula: see text] and [Formula: see text] with a molar ratio of 1:1 were selected as raw materials. One sample was undoped, and five samples were mixed with 0.4 wt.% [Formula: see text], MnO, CoO, [Formula: see text] and [Formula: see text], respectively. The experimental studies were executed under the synthetic condition of 5 GPa pressure and [Formula: see text] temperature using China-type large volume cubic high-pressure apparatus (CHPA) (SPD-6X1200). After the experiment, compositions of the synthetic jadeites were characterized by X-ray diffraction, microstructures characterized by field emission scanning electron microscopy (FESEM) and the high-resolution transmission electron microscopy (HRTEM), molecular vibration types investigated by Raman spectra. The color-causing ion of the synthetic jadeites was investigated by UV–Vis Spectra. The results show that the synthetic jadeites have excellent crystallinity and fine-grained texture and similar structural behavior with natural jadeite. UV–Vis Spectra indicated that different colors of samples have different ion absorption peaks, thus showing different colors. This experiment explored the geological conditions of synthetic jadeite by means of high pressure and high temperature (HPHT) to give a favorable experimental basis for synthetic jadeite and analyze the coloration mechanism of jadeite by way of ion-doping.

Microstructural Study of Diamond Deformed Under High Pressure and Temperature

1985 ◽  
Vol 43 ◽  
pp. 230-231
Author(s):  
E. F. Koch
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Lattice Structure ◽  
Diamond Particle ◽  
Polycrystalline Diamond ◽  
Sintering Process ◽  
Ion Milling ◽  
Sintered Compact ◽  
Transmission Electron ◽  
High Pressure Sintering

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.

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