Size-dependent phase transition of graphite to superhard graphite under high pressure at room temperature

2012 ◽  
Vol 112 (10) ◽  
pp. 103707 ◽  
Author(s):  
Cailong Liu ◽  
Yonghao Han ◽  
Quan Li ◽  
Yanzhang Ma ◽  
Yanming Ma ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Room Temperature ◽  
Size Dependent

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.

Photoacoustic determination of phase transition in BaTiO3 induced by high pressure at room temperature

2003 ◽  
Vol 74 (1) ◽  
pp. 732-734 ◽  
Author(s):  
M. Villagrán-Muniz ◽  
M. Navarrete ◽  
E. V. Mejı́a-Uriarte
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Room Temperature

Clinopyroxene-perovskite phase transition of FeGeO 3 under high pressure and room temperature

1999 ◽  
Vol 26 (3) ◽  
pp. 212-216 ◽  
Author(s):  
T. Hattori ◽  
T. Matsuda ◽  
T. Tsuchiya ◽  
T. Nagai ◽  
T. Yamanaka
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Room Temperature ◽  
Perovskite Phase

A phase transition in Ga2Se3 under high pressure

1994 ◽  
Vol 72 (9-10) ◽  
pp. 681-682 ◽  
Author(s):  
K. V. Savchenko ◽  
V. V. Shchennikov
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Thermoelectric Power ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Vickers Microhardness ◽  
Zinc Blende ◽  
Stockbarger Method ◽  
Zinc Blende Structure ◽  
Semiconductor Type

Ga2Se3 crystals with an excess of Se were grown by the Bridgman–Stockbarger method and had a defect zinc blende structure with a0 = 5.42 Å [Formula: see text] (1 Å = 10−10 m). At room temperature the resistivity was equal to (4.5 ± 1.5) × 1011 Ω cm, the thermoelectric power was (−1.1 ± 0.1) mV K−1 and the Vickers microhardness was (357 ± 9) kg mm−2. The gamma-induced conductivity was measured in the gamma-emitting power range of 3–340 rad s−1. Pressure dependencies of electrical resistance and thermoelectric power at room temperature allowed us to determine a phase transition of the semiconductor–semiconductor type at 14.2 GPa.

Reversible phase transition between amorphous and crystalline in Zr41.2Ti13.8Cu12.5Ni10Be22.5 under high pressure at room temperature

2000 ◽  
Vol 76 (20) ◽  
pp. 2874-2876 ◽  
Author(s):  
Liling Sun ◽  
W. K. Wang ◽  
D. W. He ◽  
W. H. Wang ◽  
Q. Wu ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Room Temperature ◽  
Reversible Phase Transition ◽  
Reversible Phase

Complex Hydrides Studied by Raman Spectroscopy and Thermal Conductivity Measurements under High Pressure

2006 ◽  
Vol 971 ◽  
Author(s):  
Bertil Sundqvist ◽  
Alexandr V. Talyzin ◽  
Ove Andersson
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Room Temperature ◽  
Structural Information ◽  
Temperature Phase ◽  
Current Interest ◽  
Conductivity Measurements ◽  
Large Current ◽  
Complex Hydrides ◽  
Pressure Phase

ABSTRACTThe pressure-temperature phase diagrams of alkali metal alanates and borohydrides are of large current interest, and we have recently studied phase transformations under pressure in several of these materials. We here report Raman studies of KBH4 under pressure at room temperature, showing a phase transition near 6 GPa. Although no structural information is yet available, the similarity between KBH4 and NaBH4 suggests the new structure is orthorhombic. We also report studies on LiBH4 showing that the high pressure phase of this material is metastable to zero pressure below 200 K.

Spherical hexagonal tellurium nanocrystals: fabrication and size-dependent structural phase transition at high pressure

2008 ◽  
Vol 19 (4) ◽  
pp. 045707 ◽  
Author(s):  
Zhengtao Deng ◽  
Zhongxing Bao ◽  
Li Cao ◽  
Dong Chen ◽  
Fangqiong Tang ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Size Dependent

scholarly journals Size-dependent phase transition of Er2O3 under high pressure

2018 ◽  
Vol 112 (14) ◽  
pp. 143102 ◽  
Author(s):  
Xiangting Ren ◽  
Xiaozhi Yan ◽  
Zhenhai Yu ◽  
Wentao Li ◽  
Ke Yang ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Size Dependent
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