Pressure-Induced Nano-Crystallization of Y2O3

2011 ◽  
Vol 1297 ◽  
Author(s):  
Stuart Deutsch ◽  
Jafar F. Al-Sharab ◽  
Bernard H. Kear ◽  
Stephen D. Tse
Keyword(s):  
Phase Transition ◽  
Grain Size ◽  
High Pressure ◽  
Phase Transformation ◽  
Monoclinic Phase ◽  
Transformation Process ◽  
Coarse Grained ◽  
Nanocrystalline State ◽  
Phase Transformation Process ◽  
Reversible Phase

ABSTRACTA reversible-phase transformation process to convert coarse-grained polycrystalline cubic-Y2O3 directly into the nanocrystalline state is being developed. The process involves a forward cubic-to-monoclinic phase transition under high pressure and a backward transformation from monoclinic-to-cubic under a lower pressure. The process has been used to reduce the grain size of fully dense cubic-Y2O3 from 300 μm to 0.1 μm. A surface modification effect, comprising a columnar-grained structure, has also been observed. Preliminary work indicates that the surface structure is modified, apparently formed by interaction between the graphite heater and sample.

Removal and recovery of Pb from wastewater through a reversible phase transformation process between nano-flower-like Mg(OH)2 and soluble Mg(HCO3)2

2019 ◽  
Vol 6 (2) ◽  
pp. 467-477 ◽  
Author(s):  
Xueming Liu ◽  
Kainan Song ◽  
Weizhen Liu ◽  
Yuecheng Xiong ◽  
Yunyun Xu ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Transformation Process ◽  
New Technique ◽  
Phase Transformation Process ◽  
A New Technique ◽  
Reversible Phase ◽  
Removal And Recovery

This study investigated the effectiveness of a new technique for recovering Pb as highly pure PbCO3 nanoparticles from wastewater by using a nano-Mg(OH)2 adsorbent.

scholarly journals Pressure-Induced Structural Phase Transition and Metallization in Ga2Se3 up to 40.2 GPa under Non-Hydrostatic and Hydrostatic Environments

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 746
Author(s):  
Meiling Hong ◽  
Lidong Dai ◽  
Haiying Hu ◽  
Xinyu Zhang
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
High Pressure ◽  
Phase Transformation ◽  
Transport Properties ◽  
Electrical Transport ◽  
Structural Phase ◽  
Structure Evolution ◽  
Systematic Research ◽  
Electrical Transport Properties

A series of investigations on the structural, vibrational, and electrical transport characterizations for Ga2Se3 were conducted up to 40.2 GPa under different hydrostatic environments by virtue of Raman scattering, electrical conductivity, high-resolution transmission electron microscopy, and atomic force microscopy. Upon compression, Ga2Se3 underwent a phase transformation from the zinc-blende to NaCl-type structure at 10.6 GPa under non-hydrostatic conditions, which was manifested by the disappearance of an A mode and the noticeable discontinuities in the pressure-dependent Raman full width at half maximum (FWHMs) and electrical conductivity. Further increasing the pressure to 18.8 GPa, the semiconductor-to-metal phase transition occurred in Ga2Se3, which was evidenced by the high-pressure variable-temperature electrical conductivity measurements. However, the higher structural transition pressure point of 13.2 GPa was detected for Ga2Se3 under hydrostatic conditions, which was possibly related to the protective influence of the pressure medium. Upon decompression, the phase transformation and metallization were found to be reversible but existed in the large pressure hysteresis effect under different hydrostatic environments. Systematic research on the high-pressure structural and electrical transport properties for Ga2Se3 would be helpful to further explore the crystal structure evolution and electrical transport properties for other A2B3-type compounds.

High efficient phosphate removal by lanthanum modified hydroxyapatite with a phase transformation process

2021 ◽  
Vol 216 ◽  
pp. 211-219
Author(s):  
Zhongjun Li ◽  
Qiwu Wei ◽  
Guisheng Zeng ◽  
Zhong Ren ◽  
Baojin Huang
Keyword(s):  
Phase Transformation ◽  
Transformation Process ◽  
Phosphate Removal ◽  
Phase Transformation Process ◽  
High Efficient

scholarly journals Acid–base sites synergistic catalysis over Mg–Zr–Al mixed metal oxide toward synthesis of diethyl carbonate

RSC Advances ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 4695-4702 ◽  
Author(s):  
Tingting Yan ◽  
Weihan Bing ◽  
Ming Xu ◽  
Yinwen Li ◽  
Yusen Yang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Catalytic Performance ◽  
Transformation Process ◽  
Mixed Metal Oxide ◽  
Diethyl Carbonate ◽  
Mixed Metal Oxides ◽  
Acid Base ◽  
Phase Transformation Process ◽  
Mixed Metal ◽  
Synergistic Catalysis

Mg/Zr/Al mixed metal oxides were prepared via a facile phase transformation process of hydrotalcite precursors, which showed acid–base sites synergistic catalytic performance toward the synthesis of diethyl carbonate from ethanol and urea.

Phase transformation process of Tb2O3 at elevated temperature

2019 ◽  
Vol 171 ◽  
pp. 108-111 ◽  
Author(s):  
Junyu Zhang ◽  
Hetuo Chen ◽  
Junping Wang ◽  
Dewen Wang ◽  
Dan Han ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Elevated Temperature ◽  
Transformation Process ◽  
Phase Transformation Process

Phase Transformation during the Hot Pressing of WC-40vol.% Al2O3 Composites

2012 ◽  
Vol 152-154 ◽  
pp. 260-265 ◽  
Author(s):  
Hai Xia Qu ◽  
Shi Gen Zhu
Keyword(s):  
Phase Transformation ◽  
Hot Pressing ◽  
Metal Particle ◽  
High Energy ◽  
Transformation Process ◽  
Matrix Composites ◽  
Pressing Temperature ◽  
Phase Transformation Process ◽  
Vacuum Degree ◽  
Energy Ball

WC matrix composites toughened by commercial Al2O3composed of AlOOH, χ-Al2O3and amorphous Al2O3were prepared by high energy ball milling and then hot pressed at 769°C, 984°C, 1100°C, 1540°C for 90min, respectively, to investigate the phase transformation process. Microstructure and mechanical properties of WC-40vol.%Al2O3composites were studied as well. The results showed that, with the increasing hot pressing temperature, the commercial Al2O3 transformed to α-Al2O3completely through γ-Al2O3. WC could be oxidized and decarburized to W, C and W2C at low temperature when the vacuum degree was very low. The existence of W in the composites sintered at 1540°C for 90min could contribute to a metal particle toughening effect to the composites, resulting in the achievement of an excellent fracture toughness of 10.43MPa•m1/2, combining a Vickers hardness of 18.65GPa with a relative density of 97.98% for WC-40vol.%Al2O3composites.

Monoclinic phase of boron nitride appearing during the hexagonal cubic phase transition at high pressure and high temperature

1996 ◽  
Vol 68 (2) ◽  
pp. 182-184 ◽  
Author(s):  
Shigeo Horiuchi ◽  
Lian‐Long He ◽  
Mitsuko Onoda ◽  
Minoru Akaishi
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
High Temperature ◽  
Boron Nitride ◽  
Monoclinic Phase ◽  
Cubic Phase
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