Characterization of Co-Modified γ-Fe2O3 Based Composite Nanoparticles

2014 ◽  
Vol 633 ◽  
pp. 11-16
Author(s):  
Jun Ming Li ◽  
Jian Li ◽  
Long Long Chen ◽  
Xiao Min Gong ◽  
Hong Mao
Keyword(s):  
Crystal Structure ◽  
Photoelectron Spectroscopy ◽  
Molar Mass ◽  
Chemical Compositions ◽  
Vibrating Sample Magnetometry ◽  
X Ray ◽  
Transmission Electron ◽  
Chemically Induced ◽  
Anisotropic Constant

During the synthesis of γ-Fe2O3 nanoparticles using a chemically-induced transition in a FeCl2 solution, Co-surface modification was attempted by adding Co (NO3)2 and NaOH to the solution. The magnetization behaviors, morphologies, crystal structure, and chemical compositions of the as-prepared samples were characterized using vibrating sample magnetometry, transmission electron microscopy, X-ray diffractometry, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The as-prepared particles consisted of γ-Fe2O3/CoFe2O4 composite crystallite and a CoCl2·6H2O coating. The molar, mass and volume ratios of the phases were estimated from the characterization results for each sample. The Co-modified γ-Fe2O3 nanoparticles’ anisotropic constant is approximately 1.48×10-1 J/cm3. Their coercivity depends on the size of composite crystallites, which is based on the γ-Fe2O3/CoFe2O4 content rather than the Co content.

Preparation and Characterization of γ-Fe2O3-ZnFe2O4 Composite Nanoparticles

2013 ◽  
Vol 873 ◽  
pp. 152-157
Author(s):  
Long Long Chen ◽  
Jun Ming Li ◽  
Xiao Min Gong ◽  
Jian Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Species ◽  
Composite Nanoparticles ◽  
X Ray Diffraction ◽  
Ferrite Core ◽  
Phase Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Chemically Induced

Using a chemically induced transition in an FeCl2 solution, γ-Fe2O3 nanoparticles can be prepared from an amorphous precursor composed of FeOOH and Mg (OH)2. Surface modification by adding ZnCl2 during liquid-phase synthesis was attempted. The magnetization, morphology, crystal structure, and chemical species of as-prepared samples were characterized by vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray energy-dispersive spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The experimental results showed that the surface of the γ-Fe2O3 nanoparticles can be modified by adding ZnCl2 to form composite nanoparticles with a γ-Fe2O3/ZnFe2O4 ferrite core coated with Zn (OH)2 and absorbed FeCl36H2O; this modification can be enhanced by additional NaOH.

Characterization of columns grown during KrF laser micromachining of Al2O3–TiC ceramics

2003 ◽  
Vol 18 (5) ◽  
pp. 1123-1130 ◽  
Author(s):  
V. Oliveira ◽  
R. Vilar
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Laser Pulses ◽  
Formation Mechanisms ◽  
X Ray ◽  
Reducing Conditions ◽  
Transmission Electron ◽  
Column Formation ◽  
Krf Laser

This paper aims to contribute to the understanding of column formation mechanisms in Al2O3–TiC ceramics micromachined using excimer lasers. Chemical and structural characterization of columns grown in Al2O3–TiC composite processed with 200 KrF laser pulses at 10 J/cm2 was carried out by scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction analysis. Fully developed columns consist of a core of unprocessed material surrounded by an outer layer of Al2TiO5, formed in oxidizing conditions, and an inner layer, formed in reducing conditions, composed of TiC and Al3Ti or an AlTi solid solution. Possible mechanisms of column formation are discussed.

Characterization of Al65.0Cu32.9Co2.1 Alloy Containing Nanofibres

2012 ◽  
Vol 186 ◽  
pp. 212-215
Author(s):  
Jacek Krawczyk ◽  
Włodzimierz Bogdanowicz ◽  
Grzegorz Dercz ◽  
Wojciech Gurdziel
Keyword(s):  
Electron Microscopy ◽  
Average Diameter ◽  
Chemical Compositions ◽  
X Ray ◽  
Transmission Electron ◽  
Orthogonal Set ◽  
T Phase ◽  
Terminal Area ◽  
Scanning Electron

Microstructure of terminal area of Al65Cu32.9Co2.1ingots (numbers indicate at.%), obtained via directional solidification was studied. Scanning Electron Microscopy, Transmission Electron Microscopy and X-ray powder diffraction were applied. Point microanalysis by Scanning Electron Microscope was used for examination of chemical compositions of alloy phases. It was found that tetragonal θ phase of Al2Cu stoichiometric formula was the dominate phase (matrix). Additionally the alloy contained orthogonal set of nanofibres of Al7Cu2Co T phase with the average diameter of 50-500 nm and oval areas of hexagonal Al3(Cu,Co)2H-phase, surrounded by monoclinic AlCu η1phase rim. Inside some areas of H-phase cores of decagonal quasicrystalline D phase were observed.

Synthesis and characterization of homogeneous lead-substituted tin oxide with the (110) face of rutile structure

2000 ◽  
Vol 15 (10) ◽  
pp. 2076-2079
Author(s):  
Chika Nozaki ◽  
Takashi Yamada ◽  
Kenji Tabata ◽  
Eiji Suzuki
Keyword(s):  
Electron Microscopy ◽  
Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Rutile Structure ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Synthesis of a rutile-type lead-substituted tin oxide with (110) face was investigated. The characterization was performed by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, infrared spectroscopy, x-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller surface area measurements. The homogeneous rutile-type lead-substituted tin oxide was obtained until 4.1 mol% of tin was substituted with lead. The surface of obtained oxide had a homogeneously lead-substituted (110) face.

scholarly journals Hydrogenative Cyclization of Levulinic Acid to γ-Valerolactone with Methanol and Ni-Fe Bimetallic Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1096
Author(s):  
Ligang Luo ◽  
Xiao Han ◽  
Qin Zeng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Levulinic Acid ◽  
Hydrogen Donor ◽  
Effect Of Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
Temperature Programmed

A series of Ni-Fe/SBA-15 catalysts was prepared and tested for the catalytic hydrogenation of levulinic acid to γ-valerolactone, adopting methanol as the only hydrogen donor, and investigating the synergism between Fe and Ni, both supported on SBA-15, towards this reaction. The characterization of the synthesized catalysts was carried out by XRD (X-ray powder diffraction), TEM (transmission electron microscopy), H2-TPD (hydrogen temperature-programmed desorption), XPS (X-ray photoelectron spectroscopy), and in situ FT-IR (Fourier transform–infrared spectroscopy) techniques. H2-TPD and XPS results have shown that electron transfer occurs from Fe to Ni, which is helpful both for the activation of the C=O bond and for the dissociative activation of H2 molecules, also in agreement with the results of the in situ FT-IR spectroscopy. The effect of temperature and reaction time on γ-valerolactone production was also investigated, identifying the best reaction conditions at 200 °C and 180 min, allowing for the complete conversion of levulinic acid and the complete selectivity to γ-valerolactone. Moreover, methanol was identified as an efficient hydrogen donor, if used in combination with the Ni-Fe/SBA-15 catalyst. The obtained results are promising, especially if compared with those obtained with the traditional and more expensive molecular hydrogen and noble-based catalysts.

Characterization of Fe–Ni(C) nanocapsules synthesized by arc discharge in methane

1999 ◽  
Vol 14 (5) ◽  
pp. 1782-1790 ◽  
Author(s):  
X. L. Dong ◽  
Z. D. Zhang ◽  
S. R. Jin ◽  
W. M. Sun ◽  
X. G. Zhao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Arc Discharge ◽  
Carbon Layer ◽  
Magnetization Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Energy Disperse Spectroscopy

Ultrafine Fe–Ni(C) particles of various compositions were prepared by arc discharge synthesis in a methane atmosphere. The particles were characterized by x-ray diffraction, transmission electron microscopy, energy disperse spectroscopy, chemical analysis, x-ray photoelectron spectroscopy, Mössbauer spectroscopy, and magnetization measurement. The carbon atoms solubilizing at interstitial sites in γ–(Fe, Ni, C) solution particles have the effects of forming austenite structure and changing microstructures as well as magnetic properties. A carbon layer covers the surface of Fe–Ni(C) particles to form the nanocapsules and protect them from oxidization. The mechanism of forming Fe–Ni(C) nanocapsules in the methane atmosphere was analyzed.

Preparation and Characterization of Carbon Nanotubes/Al2O3 Inorganic Hybrid Material - A Bio-Inspired Poly(Dopamine) Approach

2018 ◽  
Vol 54 ◽  
pp. 127-135
Author(s):  
Wen Zhao ◽  
Wen Cai Wang ◽  
Yong Lai Lu ◽  
Li Qun Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Oxidative Polymerization ◽  
The Self ◽  
Liquid Phase Deposition ◽  
X Ray ◽  
Transmission Electron ◽  
Cnts Surface

Carbon nanotubes/alumina (CNTs/Al2O3) nanocomposites were prepared by the poly (dopamine) assisted chemical liquid phase deposition (CLPD). The poly (dopamine) layers were firstly coated on the CNTs surface uniformly by the self-oxidative polymerization of dopamine in mild aqueous solution and then the Al2O3 nanoparticles formed on the poly (dopamine) coated CNTs surface by the CLPD. The hydrophilic poly (dopamine) layers on the CNTs surface can improve the dispersion of CNTs in aqueous solution. Moreover, it can be used as a key linker between the CNTs and Al2O3 because of the nitrogen-containing group in poly (dopamine) could coordinate with Al3+ ions. The as-prepared poly (dopamine) coated CNTs and CNTs/Al2O3 nanohybrids were characterized by X-ray photoelectron spectroscopy (XPS), X-radial diffractometer (XRD) and high resolution transmission electron microscopy (HRTEM). These results showed that the poly (dopamine) layers were coated on the surface of CNTs uniformly, and the Al2O3 nanoparticles embellished with the poly (dopamine) coated CNTs surface. Compared with pristine NR composites, the thermal conductivity of the as-prepared NR/CNTs@Al2O3 composites increased 17%.

Characterization of Changes in Properties and Microstructure of Glassy Polymeric Carbon Following Au Ion Irradiation

2009 ◽  
Vol 1215 ◽  
Author(s):  
Malek Amir Abunaemeh ◽  
Mohamed Seif ◽  
Young Yang ◽  
Lumin Wang ◽  
Yanbin Chen ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Nuclear Reactor ◽  
Ion Irradiation ◽  
Pyrolytic Carbon ◽  
X Ray ◽  
Triso Fuel ◽  
Transmission Electron ◽  
Displacement Per Atom ◽  
Polymeric Carbon

AbstractThe TRISO fuel has been used in some of the Generation IV nuclear reactor designs [1,2]. It consists of a fuel kernel of UOx coated with several layers of materials with different functions. Pyrolytic carbon (PyC) is one of the materials in the layers. In this study we investigate the possibility of using Glassy Polymeric Carbon (GPC) as an alternative to PyC. In this work, we are comparing the changes in physical and microstructure properties of GPC after exposure to irradiation fluence of 5 MeV Au equivalent to a 1 displacement per atom (dpa) at samples prepared at 1000, 1500 and 2000°C. The GPC material is manufactured and tested at the Center for Irradiation Materials (CIM) at Alabama A&M University. Transmission electron microscopy (TEM), Rutherford backscattering spectroscopy (RBS), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were used for the analysis.

Synthesis and Characterization of Co Nanoparticles by Solventless Thermal Decomposition

2007 ◽  
Vol 119 ◽  
pp. 71-74 ◽  
Author(s):  
Yan Li ◽  
Xiao Li Zhang ◽  
Young Hwan Kim ◽  
Young Soo Kang
Keyword(s):  
Crystal Structure ◽  
Thermal Decomposition ◽  
Synthesis And Characterization ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Of Nanoparticles ◽  
Co Nanoparticles

Co nanoparticles were synthesized via a solventless thermal decomposition of Co2+-oleate2. The crystalline structure is strongly affected by the thermal treatment of the Co nanoparticles. Further, the annealing also results in the decomposition of surfactant around Co particles. The size of nanoparticles was confirmed by transmission electron microscopy (TEM). The crystal structure of nanoparticles was characterized by X-ray diffraction pattern (XRD). The magnetic properties were characterized by vibrating sample magnetometer (VSM).

Characterization of Zn0.96Al0.02Ga0.02O Thermoelectric Material

2013 ◽  
Vol 802 ◽  
pp. 227-231
Author(s):  
Panida Pilasuta ◽  
Pennapa Muthitamongkol ◽  
Chanchana Thanachayanont ◽  
Tosawat Seetawan
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Single Phase ◽  
Hexagonal Structure ◽  
Hexagonal Crystal Structure ◽  
X Ray Diffraction ◽  
Hexagonal Crystal ◽  
X Ray ◽  
Transmission Electron

Crystal structure of Zn0.96Al0.02Ga0.02O was analyzed by X-Ray diffraction (XRD) technique and the microstructure was observed by scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD results showed single phase and hexagonal structure a = b = 3.24982 Å, and c = 5.20661 Å. The SEM and TEM results showed the grain size of material arrangement changed after sintering and TEM diffraction pattern confirmed hexagonal crystal structure of Zn0.96Al0.02Ga0.02O after sintering.

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