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.

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.

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.

Barium Titanium Alkoxides for Barium Titanates: Synthesis, Characterization, and Applications

1994 ◽  
Vol 351 ◽  
Author(s):  
Victor W. Day ◽  
Todd A. Eberspacher ◽  
Walter G. Klemperer ◽  
Shurong Liang
Keyword(s):  
Sol Gel ◽  
Solvent Molecule ◽  
X Ray Diffraction ◽  
Aryl Group ◽  
Barium Titanates ◽  
Acidic Conditions ◽  
Moisture Sensitive ◽  
Gel Processing ◽  
Hydrolysis Of ◽  
Alkoxide Precursors

ABSTRACTSeveral new crystalline bimetallic alkoxide precursors for barium titanates processing have been prepared: {[Ba(Solv)2]2[Ti(OAr)6]2} (1) (Solv = coordinated solvent molecule, Ar = aryl group), [Ba(CH2OHCH2OH)4(H20)][Ti(OCH2CH2O)3] (2), Ba[Ti2(OR)9]2 (3) (R = methyl, ethyl, and n-propyl), and [Ba(BzOH)Ti2O(OBz)8]2 (4) (Bz = benzyl). These precursors have been characterized by elemental analysis, IR, NMR, and single-crystal X-ray diffraction techniques. Compound 1 is well-suited for sol-gel processing of BaTiO3 powders and thin films under a variety of conditions. The facile preparation of 2 using relatively inexpensive starting materials makes it a viable alternative for the synthesis of BaTiO3 fine powders. Both compounds 3 and 4 are fairly moisture-sensitive; hydrolysis of these precursors under acidic conditions affords the formation of gels instead of precipitates. The reactivity of 3 toward hydrolysis can be tailored by varying the alkyl group.

Fabrication of ZnTiO3 Nanofibers by Electrospinning

2013 ◽  
Vol 562-565 ◽  
pp. 57-61
Author(s):  
Rong Li Sang ◽  
Jun Shao ◽  
Lin Wang
Keyword(s):  
Electron Microscopy ◽  
Chemical Sensors ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
X Ray ◽  
Ultrathin Fibers ◽  
Ft Ir ◽  
Gel Processing ◽  
Scanning Electron

Ultrathin fibers of PVP/ZnTiO3 composite were prepared through sol-gel processing and electrospinning technique. After calcined of the above precursor fibers at 600°C, the spinel ZnTiO3 nanofibers, with a diameter of 50-150nm, were successfully obtained. The fibers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fourier transform infrared (FT-IR), respectively. The results displayeded that the morphology and crystalline phase of the fibers were largely influenced by the calcination temperature. The reported strategy will be useful for fabricating one-by-one continuous nanofibers, which are suitable for applications in catalysis, chemical sensors, nanoelectrodes, and nanodevices.

Sol-Gel Processing of the Ti2Ca1Ba2Cu2O8+X High Tc Superconducting Phase

1990 ◽  
Vol 180 ◽  
Author(s):  
M. R. Teepe ◽  
D. S. Kenzer ◽  
G. A. Moore ◽  
G. Kordas
Keyword(s):  
Sol Gel ◽  
Solvent System ◽  
Superconducting Phase ◽  
Processing Conditions ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Rotary Evaporation ◽  
X Ray Scattering ◽  
Gel Processing

ABSTRACTAn alkoxide Sol-Gel system was developed to produce bulk powders of the TI2Ca1Ba2Cu2O8+x high Tc superconducting phase. Methoxyethoxide and Cu(II) ethoxide precursors were used for the formation of homogeneous sols. Solubility of the Cu(II) ethoxide was aided by using a 2-methoxyethanol/methyl ethyl ketone/toluene solvent system. The sols were characterized by small angle x-ray scattering (SAXS) and TEM. Powders were produced by rotary evaporation followed by thermal treatment in a closed container with thallium metal present at 900°C for various calcination times. Powders were characterized by x-ray diffraction, resistivity and magnetic susceptibility measurements, and chemical analysis. Samples exhibited transition onsets between 100 and 110K depending upon the processing conditions.

scholarly journals Y3+ substituted Sr-hexaferrites: sol-gel synthesis, structural, magnetic and electrical characterization

Cerâmica ◽  
2019 ◽  
Vol 65 (374) ◽  
pp. 274-281 ◽  
Author(s):  
S. S. Satpute ◽  
S. R. Wadgane ◽  
S. R. Kadam ◽  
D. R. Mane ◽  
R. H. Kadam
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Electrical Characterization ◽  
Combustion Method ◽  
Hexagonal Structure ◽  
Strontium Hexaferrite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Morphological Studies ◽  
Auto Combustion

Abstract Y3+ substituted strontium hexaferrites having chemical composition SrYxFe12-xO19 (x= 0.0, 0.5, 1.0, 1.5) were successfully synthesized by sol-gel auto-combustion method. The structural and morphological studies of prepared samples were investigated by using X-ray diffraction technique, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy. The X-ray diffraction pattern confirmed the single-phase hexagonal structure of yttrium substituted strontium ferrite and the lattice parameters a and c increased with the substitution of Y3+ ions. The crystallite size also varied with x content from 60 to 80 nm. The morphology was studied by FE-SEM, and the grain size of nanoparticles ranged from 44 to 130 nm. The magnetic properties were investigated by using vibrating sample magnetometer. The value of saturation magnetization decreased from 49.60 to 35.40 emu/g. The dielectric constant decreased non-linearly whereas the electrical dc resistivity increased with the yttrium concentration in strontium hexaferrite.

scholarly journals Leaching of Chalcopyrite under Bacteria–Mineral Contact/Noncontact Leaching Model

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 230
Author(s):  
Pengcheng Ma ◽  
Hongying Yang ◽  
Zuochun Luan ◽  
Qifei Sun ◽  
Auwalu Ali ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Surface Passivation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Leaching Process ◽  
Copper Leaching ◽  
Hydrolysis Of ◽  
Leaching Efficiency ◽  
Leaching Models ◽  
Scanning Electron

Bacteria–mineral contact and noncontact leaching models coexist in the bioleaching process. In the present paper, dialysis bags were used to study the bioleaching process by separating the bacteria from the mineral, and the reasons for chalcopyrite surface passivation were discussed. The results show that the copper leaching efficiency of the bacteria–mineral contact model was higher than that of the bacteria–mineral noncontact model. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) were used to discover that the leaching process led to the formation of a sulfur film to inhibit the diffusion of reactive ions. In addition, the deposited jarosite on chalcopyrite surface was crystallized by the hydrolysis of the excess Fe3+ ions. The depositions passivated the chalcopyrite leaching process. The crystallized jarosite in the bacteria EPS layer belonged to bacteria–mineral contact leaching system, while that in the sulfur films belonged to the bacteria–mineral noncontact system.

scholarly journals Structural and optical properties of SnO2–Al2O3 nanocomposite synthesized via sol-gel route

2015 ◽  
Vol 33 (4) ◽  
pp. 714-718 ◽  
Author(s):  
Neeraj K. Mishra ◽  
Chaitnaya Kumar ◽  
Amit Kumar ◽  
Manish Kumar ◽  
Pratibha Chaudhary ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Properties ◽  
Sol Gel ◽  
Physical Interaction ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Sensing Applications ◽  
Scanning Electron

AbstractA nanocomposite of 0.5SnO2–0.5Al2O3 has been synthesized using a sol-gel route. Structural and optical properties of the nanocomposite have been discussed in detail. Powder X-ray diffraction and scanning electron microscopy with energy-dispersive X-ray diffraction spectroscopy confirm the phase purity and the particle size of the 0.5SnO2–0.5Al2O3 nanocomposite (13 to 15 nm). The scanning electron microscopy also confirms the porosity in the sample, useful in sensing applications. The FT-IR analysis confirms the presence of physical interaction between SnO2 and Al2O3 due to the slight shifting and broadening of characteristic bands. The UV-Vis analysis confirms the semiconducting nature because of direct transition of electrons into the 0.5SnO2–0.5Al2O3 nanocomposites.

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