Dense and optical transparent CdWO4 films by sol-gel processing for scintillation applications

2007 ◽  
Vol 22 (6) ◽  
pp. 1527-1536 ◽  
Author(s):  
H.M. Shang ◽  
M. Bliss ◽  
S. Heald ◽  
T.K. Sham ◽  
F. Heigl ◽  
...  
Keyword(s):  
Sol Gel ◽  
Tungstic Acid ◽  
Cadmium Nitrate ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optical Luminescence ◽  
Optically Transparent ◽  
Rapid Sintering ◽  
Gel Processing

In this paper, we report the first successful fabrication of dense and optically transparent cadmium tungstate (CWO) films by sol-gel processing and the study of their optical and x-ray scintillation properties. A new sol-gel processing method was developed using tungstic acid and cadmium nitrate as precursors and hydrogen peroxide as solvent; homogeneous and stable CWO sols were aged at room temperature and used for the preparation of CWO films. A rapid sintering process was investigated and found to be necessary to make dense and optically transparent nanocrystalline CWO films. CWO films were uniform, fully dense, and crack-free, with CWO as the only detectable crystalline phase, as determined by x-ray diffraction. The thickness, density, grain size, and crystallinity of CWO films are all found to be strongly dependent on the sintering conditions and in turn impact the optical and x-ray scintillation properties. Sol-gel-derived dense CWO films demonstrated intense photoluminescence and x-ray excited optical luminescence intensity. The relationships between sol-gel processing, nanostructures, and optical and x-ray scintillation properties are discussed in detail.

scholarly journals Sol-Gel Template Synthesis and Characterization of Lu2O3:Eu3+ Nanowire Arrays

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 601
Author(s):  
Yahua Hu ◽  
Mu Gu ◽  
Xiaolin Liu ◽  
Juannan Zhang ◽  
Shiming Huang ◽  
...  
Keyword(s):  
Sol Gel ◽  
Nanowire Arrays ◽  
X Ray Diffraction ◽  
Aao Template ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Sol Gel Process ◽  
Optical Luminescence ◽  
Uniform Diameter

Uniform Lu2O3:Eu3+ nanowire arrays were successfully prepared by the sol-gel process using anodic aluminum oxide (AAO) templates. The as-synthesized nanowires are homogeneous, highly ordered, and dense and have a uniform diameter of ~300 nm defined by the AAO templates. The X-ray diffraction and selected area electron diffraction results show that the Lu2O3:Eu3+ nanowires have a polycrystalline cubic structure, and the crystallite size of the Lu2O3:Eu3+ nanowires is confined by the AAO template. The nanowires within the AAO template showed good photoluminescence and X-ray-excited optical luminescence performances for Lu2O3:Eu3+. The emission peaks were attributed to the 5D0 → 7FJ transitions of Eu3+ (J = 0, 1, 2, 3).

Sol-gel processing of nanocrystalline haematite thin films

1997 ◽  
Vol 12 (6) ◽  
pp. 1441-1444 ◽  
Author(s):  
L. Armelao ◽  
A. Armigliato ◽  
R. Bozio ◽  
P. Colombo
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Single Particles ◽  
X Ray ◽  
Transmission Electron ◽  
Gel Processing

The microstructure of Fe2O3 sol-gel thin films, obtained from Fe(OCH2CH3)3, was investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy. Samples were nanocrystalline from 400 °C to 1000 °C, and the crystallized phase was haematite. In the coatings, the α–Fe2O3 clusters were dispersed as single particles in a network of amorphous ferric oxide.

Gel-derived amorphous cesium-aluminosilicate powders useful for formation of pollucite glass-ceramics

1991 ◽  
Vol 6 (2) ◽  
pp. 217-219 ◽  
Author(s):  
Mari A. Hogan ◽  
Subhash H. Risbud
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Amorphous Powder ◽  
Glass Crystallization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Powders ◽  
Gel Processing ◽  
Scanning Electron

Amorphous powders in the Cs2O–Al2O3−SiO2 system were prepared by sol-gel processing. Gels made from TEOS, Al-chelate, and Cs-acetate were dried and calcined to obtain molecularly mixed powders of analyzed compositions in the range useful for conversion to pollucite (CsAlSi2O6) glass-ceramics. X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetry (TG), and scanning electron microscopy (SEM) were used to characterize the powders. A typical amorphous powder of analyzed chemical composition (in wt.%) = 28.05Cs2O, 37.77SiO2, and 37.96Al2O3 was found to have a glass transition temperature of 945 °C and a glass crystallization temperature of 1026 °C. Preliminary experimental results of densification and crystallization of the amorphous powders show pollucite/mullite phases to be present.

MgO-Al2O3-SiO2 Glass-Ceramic Prepared by Sol-Gel Method

2010 ◽  
Vol 92 ◽  
pp. 131-137 ◽  
Author(s):  
Qiu Hua Yuan ◽  
Pei Xin Zhang ◽  
Li Gao ◽  
Hai Lin Peng ◽  
Xiang Zhong Ren ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Crystallization Behavior ◽  
Glass Powder ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Green Body ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Sio2 Glass ◽  
X Ray

The crystallization behavior of MgO-Al2O3-SiO2 glass-ceramics by sol-gel technology was investigated by using x-ray diffraction (XRD), differential thermal analysis (DTA), Scanning electron microscopy (SEM). The results showed that: (1)α-cordierite phase was precipitated when the green body was calcined at 1050°C, and α-cordierite of high purity and stability could be formed at 1100°C; (2) Adding an appropriate amount of low melting point glass powder into the green body may provide liquid-phase environment during the sintering process, which will help enhance the tightness density of glass-ceramic, and thus improve its flexural strength.

Synthesis of Nano-Sized SrTiO3 Photocatalyst by Sol-Gel Method

2012 ◽  
Vol 512-515 ◽  
pp. 1673-1676 ◽  
Author(s):  
Wei Zhao ◽  
Jian Jun Yao ◽  
Jing Ya ◽  
Lei E ◽  
Zhi Feng Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Complexing Agent ◽  
Strontium Nitrate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Gel Processing

A sol-gel processing technology was employed to synthesize fine SrTiO3 powder by using strontium nitrate (Sr(NO3)2) , butyl titanate (Ti(OC4H9)4) as precursors, citric acid (C6H8O6) as complexing agent and (ethylene) glycol (C2H6O2) as stabilizer. Prepared the precursors in liquid phase and then calcined the precursors to achieve nano-sized SrTiO3 powders. The microstructure and composition of the as-synthesized samples were characterized by X-ray diffraction (XRD), Scan Electron Microscopy (SEM), and the photocatalytic activity was studied. The results showed that all the SrTiO3 particles were identified as perovskite phase. The pH values, the content of the acetic acid, the heat treat temperature play important roles on the synthesis of the SrTiO3 photocatalyst. When the pH=1, n(Sr(NO3)2 ) : n(Ti(OC4H9)4) = 1 : 1, n(Sr(NO3)2 ) : n(C6H8O6)=1:1.7, the product has better rate of photodegradation for the Methylene Blue under the ultraviolet condition.

Calcined Powder of the Sol-Gel Synthesis Hydroxyapatite

2013 ◽  
Vol 284-287 ◽  
pp. 41-45
Author(s):  
Chich Kuan Chen
Keyword(s):  
Sol Gel ◽  
Calcium Nitrate ◽  
Molar Ratio ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sintering Time ◽  
Bioactive Properties ◽  
Gel Preparation ◽  
Sol Gel Synthesis

The bioactive properties of hydroxyapatite [HA, Ca10(PO4)6(OH)2] have been demonstrated to be akin to osseous tissue, and provide quick fixation in prosthesis and orthopedics. In this study, sol-gel preparation of hydroxyapatite were arranged for Ca/P=1.67 molar ratio in calcium nitrate [Ca(NO)3.4H2O ] and triethylphosphate [TEP, C6H15PO4] and then dilute in the solvent of ethylene glycol mono-methyl ether [HOCH2CH2OCH3]. Consequently, sintering process was carried out at different temperature for various sintering time to materialize this inorganic polycrystalline phosphate. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) are applied to investigate the as dried amorphous and calcined hydroxyapatite. Results reveal calcinations at 1000oC prolonged for 30 minutes in air can exhibit crystalline hydroxyapatite.

Structural and Photoluminescence Characteristics of ZnTiO3:Pb2+ Nanofibers Produced by Electrospinning

2013 ◽  
Vol 562-565 ◽  
pp. 908-913 ◽  
Author(s):  
Rong Li Sang ◽  
Ying Chen ◽  
Qing Jun Zhang ◽  
Lin Wang
Keyword(s):  
Sol Gel ◽  
Excitation Wavelength ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
X Ray ◽  
Charge Transfer Transitions ◽  
Ultrathin Fibers ◽  
Ft Ir ◽  
Gel Processing ◽  
Scanning Electron

By sol-gel processing and electrospinning technique, ultrathin fibers of PVP/ ZnTiO3:Pb2+ composites were synthesized. After calcined of the fibers at 600°C, the spinel ZnTiO3:Pb2+ nanofibers, with a diameter of 100-200nm, were successfully obtained. The scanning electron microscopy (SEM), fourier transform infrared (FT-IR), X-ray diffraction (XRD) and photoluminescence (PL) were employed in the study. The results displayed that the morphology and crystalline phase of the fibers were greatly affecteded by the calcination temperature. The PL spectra of the samples measured at different excitation wavelength reveal a novel luminescent phenomenon in blue and green region, which can be attributed to the Pb2+-related charge-transfer transitions in ZnTiO3 nanofibers.

Preparation of Quantum-Sized Semiconductor Sulfide-Doped Gels

1992 ◽  
Vol 272 ◽  
Author(s):  
T. Gacoin ◽  
J.P. Boilot ◽  
F. Chaput ◽  
A. Lecomte
Keyword(s):  
Optical Spectroscopy ◽  
Small Angle ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Direct Precipitation ◽  
Semiconductor Particles ◽  
Optically Transparent ◽  
Thiolate Complexes

ABSTRACTUltrasmall semiconductor particles (CdS, ZnS and PbS) are produced either by direct precipitation, γ-radiolysis or in mimetic membranes. A pure cluster powder is then prepared from a chemical capping reaction. The capping of the cluster surface by thiolate complexes permits the separation of aggregates without fusion. These capped clusters can be dispersed in different solvents such as sol-gel precursors allowing to prepare dense and optically transparent xerogels with semiconductor clusters grafted on oxide polymers. The nanocrystallites are characterized by X-ray diffraction, small-angle X-ray scattering and optical spectroscopy.

Crystallization of barium titanate thin films synthesized via sol-gel processing

1995 ◽  
Vol 53 ◽  
pp. 258-259
Author(s):  
M. C. Gust ◽  
N. D. Evans ◽  
M. L. Mecartney
Keyword(s):  
Thin Films ◽  
Barium Titanate ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Independent Films ◽  
X Ray ◽  
Fine Grained ◽  
Diffraction Patterns ◽  
Gel Processing ◽  
Alkoxide Precursors

Sol-gel processing of oxide thin films offers the potential to generate different microstructures by varying process parameters such as water of hydrolysis, chemical precursor, or substrate. For this work, barium titanate (BaTiO3) thin films were prepared by the sol-gel method in order to try and generate different microstructures for dielectric measurements. However, for BaTiOs prepared using alkoxide precursors, the final microstructures of the films were found to be almost process independent. Films using different precursors, different substrates, and different amounts of water of hydrolysis all showed similar TEM microstructures. All the films after final heat treatment were polycrystalline, nanoporous, and randomly oriented BaTiO3; they were also fine-grained, with an average uniform grain size of 25-50 nm (Fig. 1). This fine-grained microstructure has also been observed in other studies of sol-gel derived BaTiO3 thin films. In addition to BaTiO3, electron diffraction patterns showed the presence of trace amounts of rutile TiO2 that were not observed by x-ray diffraction (XRD).

Preparation of Multicomponent Ceramic Powders by Sol-Gel Processing

1990 ◽  
Vol 180 ◽  
Author(s):  
J.R. Bartlett ◽  
J.L. Woolfrey
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Processing Conditions ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
X Ray ◽  
Acidic Conditions ◽  
Powder Properties ◽  
Gel Processing ◽  
Hydrolysis Of

ABSTRACTSol-gel methods have been applied to the production of the multicomponent ceramic, Synroc B. These techniques involved the hydrolysis of a mixture of Ti and Zr, alkoxides peptising to form a sol and subsequent sorption of Al3+, Ba2+ and Ca2+ cations under acidic conditions. Powder properties were examined by a variety of techniques, including electron microscopy, x-ray diffraction, N2 sorption, and differential thermal analysis. The effects of processing conditions on the physical properties of the powders are discussed.

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