Crystalline phase of Y2O3:Eu particles generated in a substrate-free flame process

Guo, Bing; Yim, Hoon; Hwang, Wonjoong; Nowell, Matthew M.; Luo, Zhiping

doi:10.1016/j.partic.2010.07.020

Cited by 17 publications

(3 citation statements)

References 28 publications

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“…There are five crystalline phases of Y 2 O 3 that have been synthesized, among which cubic and monoclinic phases are widely reported. The differences in the crystalline phases have a large effect on the energy level splitting and consequently lead to different luminescent performances. , Lanthanide dopants in Y 2 O 3 may also influence the crystalline phase of Y 2 O 3 , as it is shown that Eu concentration affects the ratio of the cubic phase to monoclinic one , and Y 2 O 3 :Eu undergoes different phases from pure Y 2 O 3 upon compression . It is known that the monoclinic phase is more stable than the cubic phase at higher temperature or at higher pressure, and cubic Y 2 O 3 may transform into the monoclinic phase above certain temperatures or pressures. , This phase transformation can be reversed by annealing Y 2 O 3 at low temperature or pressure …”

Section: Introductionmentioning

confidence: 99%

Yttrium Oxide (Y₂O₃) Nanoparticle Crystallization in Gas-Phase Synthesis: A Molecular Dynamics Study

Liu

Zhang

2021

Energy Fuels

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Y2O3 particles are widely used as the host materials for phosphors, which have shown great potential in energy and biology applications owing to their unique structure and properties. The crystal structure of Y2O3 nanoparticles is important for their properties and performance. In gas-phase synthesis, it is of particular interest how the crystalline phase initially forms from amorphous nascent Y2O3 nanoparticles, because this process provides the seed for the later evolution of the crystalline phase and thus may exert significant influence on the crystal structure of the final products. In this study, we use molecular dynamics simulations to study the initial crystal formation of Y2O3 nanoparticles at different temperatures. First, a phase diagram is derived for Y2O3 nanoparticles below 3.5 nm as a function of temperature and size. High-temperature environments favor the formation of the monoclinic phase, and large particle sizes favor the formation of the cubic phase. The large internal pressure of small nanoparticles dramatically decreases the cubic-monoclinic transformation temperature, from 1548 K for 3.5 nm to 673 K for 2.3 nm. The size enlargement during particle coalescence is an important mechanism for the crystallization of nascent Y2O3 nanoparticles in the early stage of gas-phase synthesis. Nucleation starts from the surface and quickly sweeps over the entire particle, accompanied by a temperature rise. The crystallization only occurs for an initial temperature below a critical value, e.g., 1373 K for 2 nm Y2O3 particles. For the initial temperature above the critical value, another crystallization mechanism is related to cooling after particle coalescence. In this case, the increase of the kinetic energy during coalescence is quickly dissipated to the surrounding gas molecules. A fixed cooling rate simulation shows that the crystallization can occur in this process, featured by an integral decay of atom mobility and nucleation from the core.

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Section: Introductionmentioning

confidence: 99%

Yttrium Oxide (Y₂O₃) Nanoparticle Crystallization in Gas-Phase Synthesis: A Molecular Dynamics Study

Liu

Zhang

2021

Energy Fuels

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“…Currently, the preparation methods of hollow microspheres mainly include drop method, sol–gel method, chemical vapor deposition method, template method, flame spray method, and so on. The studies about using flame spraying method to prepare porous or hollow microspheres and other hollow materials mainly focus on making use of the heat of flame field to heat reactants, and make them react with each other to generate resultants . However, there have been no reports about using the new method, which combines flame spraying technology, SHS technology, and rapid solidification to prepare hollow ceramic microspheres.…”

Section: Introductionmentioning

confidence: 99%

“…The studies about using flame spraying method to prepare porous or hollow microspheres and other hollow materials mainly focus on making use of the heat of flame field to heat reactants, and make them react with each other to generate resultants. 16,17 However, there have been no reports about using the new method, which combines flame spraying technology, SHS technology, and rapid solidification to prepare hollow ceramic microspheres. This article introduces the self-reactive quenching technology combining advantages of these three technologies, and it can further prepare the hollow multiphase microspheres rapidly with required components according to the actual situation.…”

Section: Introductionmentioning

confidence: 99%

Effect of Heat on Hollow Multiphase Ceramic Microspheres Prepared by Self‐Reactive Quenching Technology

Hongfei

Wang

Xingjian

et al. 2013

Int J Applied Ceramic Tech

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The self-reactive quenching technology, which combines flame thermal spraying technology, self-propagating high-temperature synthesis (SHS), and rapid solidification, is a new method for preparation of hollow microspheres. Based on this, the effect of heat released by different exothermic systems on preparation of hollow ceramic microspheres was studied. The results show that for low-exothermic system Si-Sucrose-NH 4 Cl, the self-propagating reactions cannot occur, and the quenching products are Si microspheres with porous structure. For the moderate exothermic system Al-SiO 2 -Sucrose, the quenching products consist of some grains, which are hollow spherical or nearly spherical particles and irregular powders. Formation of Al 2 O 3 -Si indicates possible occurrence of SHS reactions. Meanwhile, for high-exothermic system Al-Cr 2 O 3 -Sucrose-Si-Epoxy Resin, the quenching products consist of internal hollow spherical grains and irregular-shaped porous particles; the phase composition mainly contains Al 2 O 3 , Cr 3 C 2 , Cr 7 C 3 , Cr 3 Si, and mullite, showing completeness of SHS reactions. The higher the adiabatic combustion temperature of the system is, the more heat it releases is higher, and the ceramic droplets form easilier.

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Effect of dopant concentration and particle size on fluorescence properties of Y2O3:Eu3+ derived in presence of NIPAM/AAc copolymer

Fadaie

Kashani-Motlagh

Maghsoudipour

et al. 2012

J Mater Sci: Mater Electron

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Crystalline phase of Y2O3:Eu particles generated in a substrate-free flame process

Cited by 17 publications

References 28 publications

Yttrium Oxide (Y₂O₃) Nanoparticle Crystallization in Gas-Phase Synthesis: A Molecular Dynamics Study

Yttrium Oxide (Y₂O₃) Nanoparticle Crystallization in Gas-Phase Synthesis: A Molecular Dynamics Study

Effect of Heat on Hollow Multiphase Ceramic Microspheres Prepared by Self‐Reactive Quenching Technology

Effect of dopant concentration and particle size on fluorescence properties of Y2O3:Eu3+ derived in presence of NIPAM/AAc copolymer

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Crystalline phase of Y2O3:Eu particles generated in a substrate-free flame process

Cited by 17 publications

References 28 publications

Yttrium Oxide (Y2O3) Nanoparticle Crystallization in Gas-Phase Synthesis: A Molecular Dynamics Study

Yttrium Oxide (Y2O3) Nanoparticle Crystallization in Gas-Phase Synthesis: A Molecular Dynamics Study

Effect of Heat on Hollow Multiphase Ceramic Microspheres Prepared by Self‐Reactive Quenching Technology

Effect of dopant concentration and particle size on fluorescence properties of Y2O3:Eu3+ derived in presence of NIPAM/AAc copolymer

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Yttrium Oxide (Y₂O₃) Nanoparticle Crystallization in Gas-Phase Synthesis: A Molecular Dynamics Study

Yttrium Oxide (Y₂O₃) Nanoparticle Crystallization in Gas-Phase Synthesis: A Molecular Dynamics Study